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 OF THE 
 
 IRew ^ovk State College of Hgriculture 
 
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 :g.^xjL.li, 
 
Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924003613597 
 
How TO Wire Buildings : 
 
 A MANUAL 
 OF THE ART OF INTERIOR WIRING, 
 
 AUGUSTUS NOLL. E. E. 
 
 Member Amer, Inat, of Elec, Kngine&ra. 
 
 WITH MANY ILLUSTRATIONS. 
 FOURTH EDITION. 
 
 NEW YORK : 
 
 D. VAN NOSTRAND COMPANY, 
 
 23 Murray and 27 Warren Streets. 
 1 906. 
 
Copyllght, 1898 ^ 
 
 Ohableb C. Sbellby 
 
 New York. 
 
PREFACE. 
 
 It would be impossible to exaggerate the importance 
 of good wiring as an element in the prosperity and 
 permanence of the various electrical industries ; and the 
 writer of the present modest volume believes that his 
 efforts to explain the true principles of good wiring and 
 to point out the best methods will be welcomed cordially 
 by electrical engineers, contractors^ wiremen and the 
 public generally. 
 
 The idea followed in inditing these pages has been to 
 draw upon personal experiences ranging over a great 
 many years, and to set forth in plain, simple language 
 the things that must be done and the things that must 
 be avoided. Every part of the subject is treated in such 
 a manner that beginners, wiremen and others interested in 
 the practical branches of the art of interior wiring can, 
 with a little attention, understand readily why certain 
 practices are preferable to others, and how a piece of 
 work can be rendered safe and satisfactory. It is believed 
 that practical advice from one who has himself tested by 
 actual work and observation the value of every rule and 
 
IT PEBFACB. 
 
 suggestion here offered, will be very helpful. While 
 much may seem novel, no statement is made that practice 
 does not confirm, and no method is recommended that 
 experience and common sense do not approve. 
 
 There is as far as possible all avoidance of abstruse 
 technicalities in the descriptions, and the divisions have 
 been made with a view to an easier comprehension of the 
 different parts of the subject. A special series of draw- 
 ings has been made for the book which will be appreciated, 
 the author thinks, in several quarters ; and many of which 
 have long been needed. 
 
 It is hoped that a perusal of this book may lead many 
 workmen forward to the study of other books that they 
 have hitherto found too technical, so that they will then 
 be able to see how close is the relation between good work 
 and sound theory. All that the author asks credit for is 
 an earnest desire, of which this little book is the ex- 
 pression, for the perfection of an art to whose improvement 
 he has devoted all his time and thought. 
 
 AUGUSTUS NOLL. 
 New YoEK City, June, 1893. 
 
CONTENTS. 
 
 Chap. 
 
 
 
 PAoa 
 
 I. 
 
 Intkoduction, .... 
 
 3 
 
 n. 
 
 GbNKKAL CON8tDBBATION8, 
 
 5 
 
 m. 
 
 Location of Conductobb, 
 
 8 
 
 IV, 
 
 Division op Cibcuits and Distbi- 
 
 
 
 BUTION OF CtrBBENT, . 
 
 15 
 
 V. 
 
 Loss of Elbctbical Energy in 
 
 
 
 Conductors, .... 
 
 24 
 
 VI. 
 
 Plans, 
 
 30 
 
 Vll. 
 
 Conduit "Wiring, .... 
 
 33 
 
 Vlll. 
 
 SwiTCHBOAEDS, .... 
 
 49 
 
 IX. 
 
 Appliances and Connections, 
 
 51 
 
 X. 
 
 CoNVEBTER Work, 
 
 53 
 
 XL 
 
 Oteehead Wiring, 
 
 63 
 
 XII. 
 
 Fuse Wire, 
 
 66 
 
 XIII. 
 
 Insulation, 
 
 70 
 
 XTV. 
 
 Electrolysis, .... 
 
 16 
 
 XV. 
 
 Adverse Wiring Conditions, 
 
 80 
 
 XVI. 
 
 Theatre and Stage Lighting, 
 
 85 
 
 XVII. 
 
 Plans of Distribution, 
 
 95 
 
 XVIII. 
 
 Distribution of Light, 
 
 113 
 
"Vl CONTENTS. , 
 
 PAOB 
 
 Chap. XIX. Distribution of Laboe and Hints 
 
 TO Foremen, . . . . 121 
 " XX. Preliminary TO Rules, Electrical 
 
 Data, etc., . . . .125 
 
 " XXI. Rules for Ascertaining Required 
 
 Sizes of Wire, . , . .135 
 " XXII. Energy — Power, .... 140 
 " XXIII. Dynamos and Motors, . . . 14S 
 " XXIV. Pulleys, ..... 150 
 
 " XXV. Belting, . . , . . 153 
 
 " XXVI. Engines, . . . . .155 
 
 " XXVII. Conclusion, ..... 158 
 
HOW TO WIRE BUILDINGS. 
 
 CHAPTER I. 
 
 Introdttctioit. 
 
 1. In the science of electricity the question of 
 "wiring" is hardly considered, but in the appli- 
 cation of electricity from a practical and commer- 
 cial standpoint it is one of the most important and 
 difficult factors. It embraces nearly every branch 
 of what is termed "construction work." The 
 student in electricity may have sufficiently mas- 
 tered the theory of electrical currents, together with 
 a knowledge of the different definitions and terms, 
 to an extent that will enable him to "lay-out" 
 wiring, on paper, in the form of a plan, showing 
 , the different circuits, sizes of wires, etc. ; and while 
 his work may be all that is desired in the shape of 
 a plan, it will very often, even while the wires are 
 being installed, fail of its purpose, owing to the 
 conditions which exist in the building and which 
 were not considered or known at the time of making 
 the plan. The mere electrical student cannot thor- 
 
4 HOW TO WIRE BUILDINGS. 
 
 ougMy understand the "'art of wiring," because its 
 essential features are purely practical, and can only 
 be acquired by experience and strict observation. 
 
 2. On tlie other hand, the practical wireman or 
 beginner will make more rapid advancement if he 
 will confine his studies to a general knowledge of 
 electricity, sufficient to enable him to trace the 
 direction of the current in dynamos, motors and 
 appurtenances, and also in the wires, rather than 
 fill his mind with all the different theories re- 
 garding magnetism and electricity, which will 
 only tend to confuse him and make the different 
 methods and systems of wiring appear more diffi- 
 cult and complex. When once the practical branch 
 of wiring is sufficiently mastered, then will he be 
 enabled to understand theory more easily, and he 
 can gradually acquire a knowledge of the various 
 terms, and of their relation to each other. 
 
 3. I have in these pages endeavored to explain, 
 and illustrate, the more important features con- 
 tinually encountered in practical wiring, in as 
 simple a manner as possible, eliminating all tech- 
 nicalities, so that this book may prove of interest, 
 not only to the student, but also to the workman, 
 in the "art of wiring" as practically applied in 
 electric lighting and kindred purposes. 
 
HOW TO WIRE BUILDINGS. 
 
 CHAPTER II. 
 
 Q-ENERAL Considerations. 
 
 4. Electrical "construction work" covers snch 
 avast field, that, not to make the work too lengthy, 
 nor to exceed our proper limits, we will only treat 
 of that portion which relates to the "wiring" of 
 buildings, and such other branches incidental 
 thereto, for electric lighting. It is, in this branch 
 of the work, that the conditions are not fixed, and 
 that those having charge of the work must depend 
 largely on their own knowledge, judgment and 
 ingenuity. There may be, for example, a change 
 in the location or number of lamps ; change in 
 location of dynamo (in the case of an isolated 
 plant), and numerous other changes which are liable 
 to occur, and for which no provision had been 
 made, when the work was originally "laid out." 
 
 5. Ordinarily, the foreman in charge should be 
 competent: To draw a plan of each floor to be 
 lighted ; to understand and familiarize himself 
 with the physical and other conditions, and from 
 this data, proceed (leaving nothing to chance) to 
 complete the plan of the wiring work and locate 
 
6 HOW TO WIKE BUILDINGS. 
 
 the cut-outs and. switclies; locate the wires, and 
 decide on the method of distribution, and locate 
 the feeding points between the Feeders, Mains, 
 and Lamp Circuits; to decide on the most satis- 
 factory percentage of loss of energy to be allowed 
 in the different portions of the wiring system, so 
 that the Difference of Potential, or pressure at the 
 lamps, will practically be equal throughout the 
 building. 
 
 6. The foreman must also be able to compute, 
 according to the per cent, of loss, the cross-section 
 or size of wire necessary for use in the different 
 parts of the wiring system ; to determine the most 
 satisfactory kind and length of fixture, and, when 
 the wiring work is completed; to set up and run 
 (in the case of an isolated plant) the dynamo, and 
 connect same, with the wiring and the instruments 
 usually provided; to compute the width of belt 
 necessary and also the diameter and face of driving 
 pulley if belted to a pulley on shafting, and in 
 case of necessity run an engine ; and, finally, to 
 locate and repair all defects in the wiring, and 
 also slight defects in the dynamo, etc. 
 
 7. These_items form the necessary qualifications 
 to ensure satisfactory and lasting results. The suc- 
 cessful operation of the plant depends, to the g^^eat- 
 est extent, on the manner in which the wiring was 
 
HOW TO WIRE BtrtLDINGS. 7 
 
 "laid out," and electric lighting companies can 
 trace the greatest part of the dissatisfaction on the 
 part of their customers to the defective manner in 
 which the wiring work was installed. 
 
HOW TO 'WIRE BUILDINGS. 
 
 CHAPTER III. 
 
 Location of Conduotobs. 
 
 8. It is sometimes the case in installing wires in 
 buildings that, although the best grade of materi- 
 als, of the several kinds usually employed for the 
 work, was used, the results have been unsatisfac- 
 tory ; the workmanship and appearance may have 
 been all that could be desired, and yet in a short 
 time after the current has been in use the work 
 breaks down, and short circuits, grounds, leaks, 
 etc., are of common occurrence. The fault is usu- 
 ally due to the location of the wires. 
 
 9. The following adverse conditions should be 
 avoided as much as possible, and where it is im- 
 possible to do so, proper safeguards, according to 
 the condition, must be provided : Excessive moist- 
 ure, atmospheric changes, extreme variations of 
 temperature, extremely high temperature, gases, 
 acids, lye, lime, cement, etc., and last, but one of 
 the most important conditions, mechanical inter- 
 ference. 
 
 10. In dealing with the first class of conditions 
 the best plan, of course, is to shun dangerous 
 
HOW TO "WIRE BTJILDINGS. 9 
 
 places, but the location of the lamps may make it 
 impossible. G^enerally, the best grade of materials 
 and superior workmanship will lessen the chances 
 of trouble, and with the high grade materials, as 
 now manufactured, very little trouble should be 
 experienced. 
 
 11. By the use of conduits (see chapter on con- 
 duits) and high grade moisture-proof wire, pro- 
 viding a separate conduit for each wire, the results 
 have been most satisfactory. Special care should 
 be taken to have the joints, on both the wire and 
 conduits, water-tight, and equally as well insu- 
 lated as the remainder of the wire and tube form- 
 ing the circuit. The cut-outs and switches should 
 be grouped and located in places free from the 
 deleterious conditions above noted. 
 
 12. The lamps, sockets and fixtures should be 
 designed with a view to protecting the electrical 
 connections contained therein. Keyless sockets 
 should be used, and the lamps should be controlled 
 by switches. The lamp should be provided with 
 an extra safeguard, arranged to exclude moisture 
 and gas. The design of these is generally similar 
 to that of a fruit jar, or bulb of thick glass her- 
 metically sealed by means of rubber bushings and 
 metallic cover. If the style of work is what is 
 
10 HOW TO WIRE BUILDINGS. 
 
 known as "open" or "exposed" work, the use 
 of conduits, in many cases, will be unnecessary, 
 but care must be taken to keep the conductors free 
 from contact with the building, which can usually 
 be accomplished by the use of suitable insulators. 
 
 13. In dealing with conditions that come under 
 the head of mechanical interference, care must be 
 taken to locate the conductors and all appurte- 
 nances used in the wiring work in such places that 
 while they are of easy access to persons in charge, 
 they are still inaccessible to inquisitive, unin- 
 formed and malicious persons. 
 
 14. When installing wires in a building in the 
 course of erection, be careful to isolate and prevent 
 contact with the work of other mechanics as much 
 as possible. As the building is in a rough state, 
 the wires must be handled with care to prevent 
 abrasions in the insulation. The nature of the 
 material forming the insulation will not admit 
 of rough treatment, such as dragging along the 
 rough floors, or across piles of brick and mortar, 
 etc. In short, the wires should be so treated that 
 the insulation covering them will not be bruised, 
 cut or perforated in the slightest degree. In an 
 otherwise perfect insulation the most minute dis- 
 arrangement of its parts will often impair its use- 
 
HOW TO WIBE BUILDINGS. 11 
 
 fulness and permanence, and while, in some cases, 
 the defect will at once become evident, still, in 
 other instances, the fault may not appear until 
 after the work has been in use for some time, when 
 remedying the defect will cause expense and ex- 
 treme annoyance, and will necessitate the cutting 
 of the plaster on the side walls or ceilings. 
 
 15. The destruction of the insulation, due either 
 to natural deterioration, or other causes, is the 
 greatest source of trouble in electric lighting (see 
 chapter on electrolysis). Hence the use of inferior 
 insulated wires is always false economy. 
 
 16. Keep the work clear of and at some dis- 
 tance from places where exposed wood-work is to 
 be fastened, such as the trim of doors, windows, 
 chair-rails, picture mouldings, base-boards, etc., as 
 these places will be plastered, and should the Avires 
 or conduits be located at these particular points, 
 their liability to being cut by nails is very probable. 
 
 17. "When wires are placed under the floors or 
 between partitions, they should be separated from 
 each other and fastened beyond the reach of the 
 floor nails or lath nails. Inaccessibility of the 
 conductors should be avoided as much as possible, 
 and concealment of same should only be resorted 
 to where definite channels, such as conduits, have 
 
12 HOW TO "WIRE BTTILDINGS. 
 
 been provided. Do not sacrifice necessary safe- 
 guards for a neat appearance, and do not "fish." 
 electric light conductors, in the same manner as 
 burglar alarm, annunciator, electric bell and such 
 like conductors usually are. In the latter cases 
 the wires are "fished" or threaded here, there and 
 everywhere, so that they may be hidden from 
 sight, but in the case of lighting circuits, no con- 
 ductors should be inserted in a channel unless the 
 exact condition of same is known. In this case 
 you are dealing with horse-power, and nothing 
 must be left to chance. Wires installed in build- 
 ings must not be treated according to the apparent 
 conditions. In every case a personal inspection by 
 one experienced in this branch of the work is the 
 only safe method. 
 
 18. Marble and tiled floors, etc;, should be 
 avoided as a place to locate wires whether con- 
 duits are used or not. In cleaning such floors, sul- 
 phuric acid is made use of; and materials of this 
 nature absorb moisture, which will, in addition to 
 the action of the acid, create another source of 
 trouble. Regarding moisture and like conditions, 
 no building for electric lighting purposes can be 
 assumed to be dry. While it may have been dry 
 at the time of installing the wires, the probability 
 of this condition being changed is so great that as 
 
HOW TO WIBE BUILDINGS. 13 
 
 a safe rule it should be treated as damp and the 
 corresponding grade of material used as though it 
 were continually damp or wet, because the water- 
 pipes may leak or burst, or the bath-tub or basins 
 may overflow. 
 
 19. When wires are encased in wood mouldings, 
 the latter should consist of a grooved back board 
 and a tight fitting cover, and in stores and similar 
 places the ceilings should be kept clear of same 
 as much as possible. A separate groove should be 
 provided for each wire, and in no case should wires 
 of the same or different polarity, forming different 
 circuits, be placed in the same groove. That style 
 of wiring should never be made use of in places 
 where adverse conditions exist. 
 
 20. In hotels, office buildings, residences, etc., 
 locate all the appliances, main and feeding Unes, 
 in hallways or closets, so as not to have to enter 
 rooms. The annoyance of interference, both to the 
 inmates and workmen, may thus be obviated while 
 the work is being installed. It will also obviate 
 annoyance in the future, when repairs, renewals or 
 alterations • may be" necessary. In workshops, fac- 
 tories, etc., the wires are usually held to the ceil- 
 ing by means of cleats, or fastened to porcelain 
 knobs. The wires should always be located in 
 
14 HOW TO WIRE BUILDINGS. 
 
 sucli places on the ceiling as are clear of shafting, 
 belts, etc., and where the work can proceed with- 
 out interruption either to the wiremen or the hands 
 -and machinery employed on the premises. 
 
HOW TO WIRE BUILDINGS. 15 
 
 CHAPTER IV. 
 
 Division of Circuits and Distribution of Cur- 
 rent. 
 
 21. Wlien the building has been inspected and 
 the various conditions in the different parts have 
 been noted, the question of distributing the cur- 
 rent then demands attention. The most impor- 
 tant considerations are the equalization of pressure 
 throughout the different lamp circuits, and to di- 
 vide the circuits according to the manner in which 
 the lamps will be used. In a building where the 
 wires are to be concealed (new structure) the best 
 mode of procedure is to locate the various closets 
 or boxes for the reception of the cut-outs and 
 switches. The location is governed by the number 
 of lights, and size and shape of the building. Gen- 
 erally from four to eight lamp circuits are carried to 
 each box. The box should be, as nearly as possi- 
 ble, in the centre of the space, the lamps in which 
 are supplied vsdth current by the circuits center- 
 ing at this box. After locating the box and divid- 
 ing the lights into circuits, the next step is to de- 
 cide upon the method of dividing and connecting 
 
16 HOW TO WIRE BXJILDIIS-GS. 
 
 the main and feeder wires. The number of mains 
 and feeders depends upon the size of the building 
 and number of lights. Locating the connecting 
 points between the mains and feeders depends upon 
 the location and number of lights at each box or 
 ramifying point, the distance between the various 
 feeding points and the use of the lights. That is 
 to say, in one part of the structure the lamps may 
 be used continuously, and in another part only a 
 few out of a great many may be used at any one 
 time. The building should be cut up or divided 
 into sections. Either each floor or each side of the 
 building should comprise a separate circuit, accord- 
 ing to the size of the building (see chapter on ex- 
 planation of distribution). If divided perpendic- 
 ularly, one or more mains feeders are provided, ex- 
 tending from the main switchboard in the dynamo- 
 room to the central point between the feeding cr 
 connecting points on the line of the mains. The 
 mains are usually run from the top to the lowest 
 floor, and at each floor connections are made to 
 wires which carry the current to the different lamp 
 circuits. These floor mains connect to one or two 
 cut-out boxes. If they are located somewhat closely 
 together, then only one set of main wires are re- 
 quired; but should the distance between them be 
 great, the floor main must extend to a point mid- 
 
HOW TO WIRE BUILDINGS. 17 
 
 way between them, and again be divided, so that a 
 branch from each will connect with the lamp cir- 
 cuit independent of the other. 
 
 Should the structure be composed of numerous 
 floors, it will be the best plan, instead of connect- 
 ing the main feeder from the dynamo-room to the 
 mains in the central point, to provide a set of sub- 
 feeders starting and connecting with the main 
 feeders at its terminals, which should extend both 
 ways and connect with the vertical mains at a 
 point about one-quarter of the whole distance from 
 the end. The idea of feeding in this manner is to 
 equalize the lighting ; that is, to balance the elec- 
 trical pressure and the number of lamps in use, so 
 that the variations constantly occurring will not 
 affect the pressure to an extent where the life of 
 the lamps will be shortened. 
 
 22. The various systems of feeding all tend to 
 this, as is shown in the plans (see chapter on same). 
 From these it will be seen that the circuits are con- 
 stantly being divided into smaller sections, so that 
 the electrical pressure is practically the same 
 throughout, and that each branch is, to a certain 
 extent (electrically), independent of the others. 
 
 When "laying out" the feeding lines, not only 
 should the work be done with a view to equalizing 
 the pressure on the wire with the full load on, but 
 
18 HOW TO WIRE BUILDINGS. 
 
 also for periods when only a few lamps are in use 
 on any one branch, while in still another all the 
 lamps were in use, so that the variation of pressure 
 on the conductors connecting with the few lights 
 will be reduced to a minimum. To accomplish 
 this, it is at times necessary to install two or more 
 sets of feeders, connected at the same main con- 
 ductors, but at different locations. Again, in other 
 instances, such as a large isolated plant, or where 
 the lighting covers a large area, it is necessary, in 
 order to equalize the electrical pressure at the 
 lamps, to provide and connect in the main feeder 
 circuits regulating devices for controlling the pres- 
 sure. 
 
 23. In a plant where the loss of electrical energy 
 in the conductors has been computed at a high 
 rate, the pressure at the lamp will be at the rated 
 amount only when all the lamps are in use; and, 
 should only one-half be in use on any one section, 
 the percentage of loss in that section will be only 
 one-half of that in which all the lamps are in use. 
 Consequently, the pressure on the wires in the sec- 
 tion where only one-half are used will be greater 
 than that at which it was rated, and the result 
 would be excessive breakage of lamps. 
 
 To overcome this defect is the function of the 
 pressure equalizer. It may not be amiss to here 
 
HOW TO WIRE BUILDIHTGS. 19 
 
 explain wh.at work the equalizer performs and the 
 diiference between it and a pressure regulator. 
 
 24. A PRESSURE REGULATOR generally consists of 
 a cOil or numerous coils connected in the field or 
 magnetic circuit and is usually (at the present 
 time) controlled automatically, although regulat- 
 ing instruments are constructed which can be gov- 
 erned by hand. The coils are placed directly in 
 the magnets, as in a compound wound machine, or 
 by the use of magnets, all or any part of the coils 
 can be thrown in or out of the field circuit. As the 
 lamps are connected or disconnected on the various 
 circuits, so will the strength of the pressure in- 
 crease or decrease. As the pressure increases, the 
 coil or coils are thrown in circuit, and, according 
 to their resistance, the pressure is decreased until 
 it is at its normal strength. The pressure is kept 
 at a constant strength at the dynamo brushes. 
 
 Should there be two or more independent sets of 
 feeders carrying current to different parts of tha 
 structure, and on one set all the lamps be in use, 
 the pressure at the lamps in this section would be 
 normal; but if on another only a few out of a 
 large number of lamps were in use, the pressure 
 would be greater than that at which it was rated. 
 The pressure required for the lamps, plus the per- 
 centage of loss in the conductors (assuming no losa 
 
20 HOW TO WIRE BUILDINGS. 
 
 on the line witli only a few lamps in use), would 
 equal the pressure at these particular lamps, and if 
 the percentage of loss was computed at 10 per 
 cent., then this amount would represent the in- 
 creased pressure. To overcome this and equalize 
 the pressure on this particular line without affect- 
 ing the pressure on the other circuits, the equal- 
 izer is used. It consists of a coil or numerous 
 coils, divided in sections and connected to plates 
 fastened to a slab of slate known as the equalizer 
 face board. The coils are thrown in or out of the 
 feeder circuit by means of a movable connecting 
 plate fastened to a handle. In the case of a pres- 
 sure regulator, the diameter of the wires is small, 
 as they only carry the amount of current carried 
 by the magnet wires, but the equalizer being con- 
 nected directly in the circuit, it must have sufficient 
 carrying capacity to carry the full amount of the 
 current necessary, according to the number of 
 lamps on the circuit, without heating. The size 
 and length of the wire forming the coils depend 
 upon the number of lamps and the percentage of 
 loss allowed in the conductor. Where several sets 
 of feeders are used, each set should be provided 
 with an equalizer. The equalizer is connected on 
 one side of the circuit only, in a similar manner to 
 a one-pole switch. Throwing the coils in or out of 
 
HOW TO WIEE BUILDINGS. 31 
 
 the circuit is governed by the indications, as shown 
 on the scale of the pressure indicators, which are 
 provided and. set in a place near the equalizer face 
 board. The indicator is connected in the circuit 
 by a set of pressure wires which connect with the 
 circuit at the center of distribution, and as the 
 pressure varies at that point, the amount of varia- 
 tion will be indicated by the needle as it travels 
 across the scale of the indicator, so that should the 
 instrument indicate excessive pressure at the cen- 
 ter of distribution, the current can be brought to 
 normal strength by connecting or throwing in the 
 circuit sufficient coils, the combined resistance of 
 which will decrease the pressure to an extent where 
 it will be equal to that required by the lamps to 
 keep them up to their rated candle-power. 
 
 25. To return to the subject of distribution again. 
 The number of circuits should be as many as prac- 
 ticable ; the greater the number, the less the vari- 
 ation that can ensue. 
 
 The system, as explained, is known as the 
 "panel" or "grouping" system, and is princi- 
 pally used in new structures, office buildings, 
 hotels and such structures. In factories, stores, 
 etc., the method of distributing the current in 
 the main and feeders is the same, but the lamp 
 circuit wires, instead of being grouped, are con- 
 
22 HOW TO WIKE BUILDISraS. 
 
 nected at the nearest point with a ceiling or floor 
 main which extends' through the whole length of 
 the building. The lamp circuits terminate in a. 
 cut-out which is connected to the mains. The 
 wires are either exposed or covered by grooved 
 wood mouldings. In all structures where the con- 
 ditions are such that all the lamps on certain cir- 
 cuits are used at a given time, it is preferable ta 
 connect them to a special, independent feeder, so 
 that the pressure on the circuits connected to the 
 lamps used at intervals can be more nicely regu- 
 lated. 
 
 The lamps that are usually turned on and off at 
 stated times, or which are only used on special 
 occasions, are generally the entrances, hall, stair- 
 ways, reading and waiting rooms, etc. 
 
 26. In all wiring installations the public lights 
 should form a separate circuit. 
 
 The public lights are generally those in public 
 parts of the building, and also generally include 
 the engine-room, cellar, etc. 
 
 All residences, hospitals, etc., should be pro- 
 vided with a night circuit, having one or more 
 lights in the hallway on each floor, and connected 
 in such a manner that they can be connected or 
 disconnected from one or more places, and can also 
 be connected to the burglar alarm and light auto- 
 
HOW TO "WIRE BUILDINGS. 23 
 
 matioally in a time of danger. This circuit is a 
 ^reat accommodation in case of sickness, sudden 
 alarm, etc. 
 
24 HOW TO WIRE BUILDINGS. 
 
 CHAPTER V. 
 
 Loss OF Eleoteical Ettekgt in Condtjctoks. 
 
 37. The expression "percentage of loss," when 
 used in connection with electric lighting, signifies 
 the amount of electrical energy expended in the 
 conductors and is due to their resistance. The 
 rate is governed by the local conditions, but, usju- 
 ally, wiring connected to mains from central sta- 
 tions is figured on a basis of two per cent, loss, and 
 wiring for isolated plants at five per cent. loss. 
 To a certain extent, it is governed by financial con- 
 ditions, that is, the percentage of loss is increased 
 in cases where fuel is cheap or when water-power 
 is used. As a general rule for ordinary isolated 
 plants it may be stated thus: Decrease the loss 
 and the cost of maintenance is lessened, but de- 
 crease the percentage of loss and the first cost is 
 increased. It is preferable to slightly increase the 
 first cost by wiring at a low rate of loss because the 
 decreased cost of maintenance will more than offset 
 the difference in first cost in generating the cur- 
 rent by the saving in fuel. The liability to exces- 
 
HOW TO WIRE BUILDINGS. 25 
 
 sive lamp breakage is also obviated when the per- 
 centage of loss in the conductor is low. 
 
 28. The first cost, assuming the boiler, engine, 
 etc., to be already installed, consists of the gener- 
 ating apparatus and its appurtenances, wire, ap- 
 pliances, fixtures, lamps and cost of labor for 
 installing same. With proper care, the generating 
 apparatus, its appurtenances, wire appliances and 
 fixtures, will not depreciate to any considerable 
 extent. Therefore, the cost of maintenance con- 
 sists chiefly in the amount of fuel, necessary for 
 generating current and the renewal of lamps. 
 The first item is governed by the amount of cur- 
 rent required to maintain the rated candle-power in 
 each lamp. (See formula electrical energy.) 
 
 The renewal of lamps depends largely on the 
 breakage due to the action of excessive current. 
 When the pressure is normal, the action of the 
 current in passing through the carbon is such that 
 the carbon is gradually decomposed and disrupted 
 to an extent that finally the carbon breaks. Under 
 ordinary normal conditions the lamp will give con- 
 tinual service for from 600 to 1,500 hours. This is 
 termed "the life of the lamp," but should the elec- 
 trical pressure vary so that at certain times it is 
 greater than the strength required, the carbon will 
 
36 HOW TO WIRE BUILDINGS. 
 
 \)e overtaxed ; the strain will be too great, the dis- 
 ruptive action will be increased and the carbon will 
 become defective and weak, and usually in a short 
 time it will break. The amount of coal consumed 
 is governed by the amount of electrical energy 
 generated in the dynamo, and if ten per cent, of 
 the electrical energy is required to overcome the 
 l-esistance in the conductors, then practically ten 
 per cent, of the total amount of fuel used is the 
 ■cost of carrying the current from the dynamo to 
 the lamps. From this it will easily be seen that 
 the question of percentage of loss in the conductors 
 must be most carefully considered, not only from 
 an electrical but also from a commercial stand- 
 point. Another important consideration is to have 
 the percentage of loss distributed properly in the 
 different conductors forming the circuit. The most 
 general and satisfactory method is, assuming the 
 loss to be five per cent., to allow one-half per cent. 
 in the lamp circuit, one per cent, in the floor 
 mains, one and one-half per cent, in the vertical 
 mains and two per cent, in the main feeders. 
 
 While the term "percentage of loss" indicates a 
 loss of energy between the dynamo and lamps, 
 commercially it is considered as the cost of trans- 
 mission, and, if intelligently considered, will not 
 be treated as a waste of power, but as a legitimate 
 
HOW TO WIRE BUILDINGS. 27 
 
 item in tlie cost of lighting. No energy can be 
 transferred without loss or cost. 
 
 29. To demonstrate the principle more clearly, 
 assume a lamp located at a distance of 1,000 feet 
 from the dynamo. The resistance of the lamp (the 
 resistance of lamp is always figured at the time the 
 lamp is hot, or at incandescence) is 90 ohms, and 
 it requires, to bring same to its rated candle-power, 
 a current of one-half ampere at 45 volts. "We will 
 decide to lose ten per cent, of the electrical energy 
 in the transmission of the current from the dy- 
 namo to the lamp, in the conductors. If the difPer- 
 ence of potential at the brushes of the dynamo = 45 
 volts, the difference of potential at the lamp would 
 equal 45 volts — ten per cent, loss = 41.5 volts. But 
 we wish to get a pressure of 45 volts at the lamp, 
 which is necessary to bring the lamp to its rated 
 candle-power. Therefore, 45 volts only represent 
 90 per cent, of the pressure. Thus 60 volts = the 
 pressure at the dynamo brushes. This lamp hav- 
 ing a resistance of 90 ohms; 2,000 feet of wire 
 being required to connect same with the dy- 
 namo ; ten per cent, being the loss expended in 
 the conductors,- and 90 ohms representing 90 per 
 cent, of the total resistance of the circuit, the 2,000 
 feet of wire must equal, in resistance, ten per cent. 
 
28 HOW TO WIEB BUILDINGS. 
 
 of the entire circuit, which is 10 ohms. Now, to 
 find the electrical energy expended in the conduct- 
 ors and lamp expressed in watts (see formula) : 
 
 ^^^ = 0^/2 and Ox ^ = watts = j^ x 45 = 22j4 
 
 watts expended in lamp, and J4 X 5 = 2>^ watts 
 expended in conductor. Or, O^ X R = watts. 
 
 Therefore, 
 
 .5 X .5 X 90 =: 22.5 watts expended in lamp, and 
 .5X.5X10= 2.5 ". " "conductor. 
 
 In both of the preceding instances it was shown 
 that the lamp required one-half ampere at 45 volts ; 
 consequently a greater pressure was required at 
 the dynamo to allow for the "drop" in the con- 
 ductors. In this last case it required 5 volts, 
 making the difference in potential at the brushes 
 of the dynamo 50 volts, the combined resistance of 
 the lamp and conductors being 100 ohms. Con- 
 sequently the current consumed on the entire cir- 
 cuit = _^^ ^f ^ = ]/2 ampere. But this yi ampere 
 100 ohms 
 
 is developed at a pressure of 50 volts. Therefore, 
 it required more power in watts, as 50 volts X .5 
 
HOW TO WIRE BUILDINGS. 29 
 
 ampere = 25 watts = tlie power required for lamp 
 and conductor. 
 
 From this it will be seen that the question of 
 percentage of loss must be carefully considered, not 
 only from a financial, but also from an electrical, 
 standpoint. 
 
30 HOW TO WIKE BUILDINGS. 
 
 CHAPTER VI. 
 
 Plans. 
 
 30. The plans generally used for showing elec- 
 tric light wiring work are what is known as Floor 
 and Elevation plans. 
 
 The Floor plan represents everything as being 
 flat, and on it are jnarked the outlets, showing the 
 number of lamps to each, and whether from the 
 side or the ceiling ; the size and location of the 
 wires forming the lamp circuits and the lamps 
 which are to be connected to each ; also the size, 
 style and location of cut-outs and switches. 
 
 The Elevation plan should show the number of 
 sets of feeders and mains, the exact location of 
 points of connection between the feeders and mains, 
 and between the mains and sub-mains which con- 
 nect with the lamp circuits either at the grouping 
 point or where the cut-outs are located along the 
 ■ceiling, as in factories or in general open work. 
 The style, size and location of main cut-outs and 
 switches should also be shown. In the ordinary 
 two-wire system it is usual to show only one wire, 
 it being understood in this case that the wires 
 
HOW TO WIKB BUILDINGS. 31 
 
 forming the other side of the circuit will run par- 
 allel with the one shown on the plan, and that 
 the cross-section is to be the same. 
 
 31. In formulating a plan of wiring it is best to 
 be familiar with the nature of the structure, so 
 that the wires may be fastened in places where the 
 mechanical conditions are favorable. 
 
 While the "runs" should be as straight and 
 short as possible, still the drilling of walls and 
 partitions must be considered. In some cases it is 
 cheaper to lengthen the circuit; that is, run the 
 wires at an angle to those already in place, so as 
 to form a turn and run somewhat out of the way, 
 or so as to obviate the necessity of cutting through 
 a thick brick or stone wall ; or, in another instance, 
 to have the wires free from the interference of 
 steam pipes, leaks of pipes, etc. 
 
 It is preferable to make an examination of the 
 premises before laying out the work on the plan. 
 
 The plan should be arranged to show all the 
 different circuits and appliances as plainly as pos- 
 sible. 
 
 A good method is to designate all the different 
 cut-outs and switches by a letter of the alphabet, 
 and on a separate sheet or on the margin of the 
 plan, refer to same. The quantity of each appli- 
 
32 HOW TO WIRE BUILDINGS. 
 
 ance, and the amount of each size of wire, will in 
 tliis way be an easy matter to estimate. 
 
 32. When the work is completed, the plans, 
 together with any alteration, either in the number 
 or change in location of lights and change of loca- 
 tion or size of wire, should be returned to the com- 
 pany. A report on the changes, and by whose 
 authority the same were made, should also be 
 submitted. 
 
HOW TO WIEE BTJILBINGS. 33 
 
 CHAPTER VII. 
 
 "CONDtriT WlBING." 
 
 33. When concealing wires, either by threading 
 them between the partitions, or under the floors, 
 or embedding them in the plaster, so that when 
 covered they are totally inaccessible, the insulation 
 is subject to deterioration and impairment due to 
 various causes which may disarrange the lighting 
 system of the light and cause failure or a fire. 
 
 It is well known that the best insulated wires 
 w^ill withstand the action of lime, cement, alkalies, 
 etc., for only a short time. The insulation will 
 then be useless for the purpose. The natural out- 
 come is that the circuit must be rewired, which 
 usually means but a choice of evUs. 
 
 The plaster must either be cut, or the carpets, 
 floor, etc., must be torn up to get at the wires. 
 The wires can be run on the surface and covered 
 with wood moulding, but this is not desirable in 
 decorated places. These same conditions confront 
 us when additions or alterations are necessary. 
 Buildings wired for so-called "future use" prove, 
 in the majority of cases where it is proposed to 
 
34 HOW TO WIBB BUILDINGS. 
 
 use the wiring a few years aiter, to be unfit to turn 
 the current on, and the re-wiring generally costs 
 more than the original work. Tinkering with the 
 wires already installed would simply be false econ- 
 omy. The materials used in electric lighting are 
 affected by conditions which are not considered in 
 gas lighting, but there is no reason why the work 
 should not be equally as permanent and successful 
 as good gas piping. This can only be accomplished 
 by arranging all 'the conductors and appliances in 
 such a manner that the whole wiring installation 
 is accessible, but defacing the walls and ceiling i& 
 objectionable and must not be attempted. 
 
 34. It is therefore necessary to locate the wires 
 in places out of sight yet all accessible. To do 
 this it is necessary to form channels in the walls 
 and under the floors for the reception of the wires 
 exclusively. The cheapest, safest and most prac 
 tical method is to provide conduits and boxes for 
 purposes, of branching and as receptacles for the 
 cut-outs and switches. These boxes are also used 
 for the purpose of withdrawing or inserting wires, 
 and may be cohsidered as a hand-hole, similar to 
 a manhole used for underground work. 
 
 The conduits not only form an extra mechanical 
 protection to the wires, bat also exclude those 
 elements which generally render the insulation on. 
 
HOW TO WIRE BUILDINGS. 35 
 
 the wires worthless. Ordinarily it is impossible, 
 except at a great expense, to change the system of 
 lighting from the two to the three-wire system, or 
 vice versa, or, from 100 to 50-volt lamps. The use 
 of conduits admits of any practical change either 
 in the system or in the number of lights. 
 
 Buildings can be equipped with conduits (instead 
 of wiring) for future use, and the insertion of wires, 
 is unnecessary until the actual time of service, and 
 at a very small increased cost. 
 
 For electric lighting purposes, no wire should be 
 inserted in undefined channels, such as between 
 .floor and partition, because the conditions existing 
 in the channel are unknown ; they may change at 
 any, time, and the result is a matter of chance and 
 peril. 
 
 35. The conduit should be constructed of such 
 materials as will meet the requirements of the pur- 
 pose, and the diameter of the bore should be ample 
 for the conductor. They should be installed in a 
 manner somewhat similar to that of wire. The 
 most essential features to be considered are > the 
 completeness of system as to points of accessibility 
 and absolute continuity of the tubes or wire-ducts. 
 
 The conduit system consists of joining together 
 lengths of the tubes, using elbows where turns and 
 bends are necessary. When the length or number 
 
36 HOW TO WIRE BUILDINGS. 
 
 of turns or bends in a circuit are such, that the in- 
 sertion of the wire becomes difficult, angle or " fish- 
 ing " boxes must be provided so that it will be an 
 easy matter not only to insert, but to withdraw the 
 conductor. Junction boxes, according to the direc- 
 tion and number of branches, must also be pro- 
 vided. The boxes act as a receptacle for the cut- 
 outs, keeping them out of sight, and imparting a 
 finished appearance to the work. 
 
 The conduit must be continuous ; from outlet to 
 outlet, from box to outlet, and from box to box. 
 Care must be taken to have all joints, either at the 
 coupling or the box, water-tight, and well insu- 
 lated. The inner surface of the tube must be in 
 alignment throughout ; that is, no shoulders or im- 
 pediments should be created, so that the insertion 
 of the wires can be done quickly and without 
 trouble. In a system of conduits embracing all 
 the favorable features, the insertion of wires in the 
 conduits can be deferred until the building is act- 
 ually completed. The cut-outs and switches can 
 be inserted and connected at the same time. The 
 metal parts will remain bright and clean, and the 
 troubles usually encountered in new buildings, due 
 to corrosive connections, are in this case obviated 
 
 The insertion of drawing-in strings at the time of 
 installing the tubes must not be relied upon. The 
 
HOW TO WIRE BUILDINGS. 37 
 
 o 
 
 C5 
 
38 HOW TO WIRE BUILDINGS. 
 
 tube must be considered empty, and installed in 
 such, a manner that should the drawing-in string 
 break, the insertion of the wires can still be easily 
 effected. 
 
 Where the conditions are adverse to ordinary 
 wiring, the use of conduits carefully installed will 
 generally meet all the difficulties. 
 
 36. The conduits and boxes should be located in 
 the halls or public parts of the building as much 
 as possible, so that additions and renewals can be 
 made without annoyance to the tenants. The bends 
 and turns should occur as near the ends of the lines 
 of conduit as possible, it being easier to insert wires, 
 more perfect control being had over the fish wire. 
 The conduits should be so arranged that a point of 
 entrance is obtained at each outlet, as shown in 
 Fig. 1, so that the work of insertion may be quick- 
 ly accomplished. It also admits of alterations 
 being made quickly. 
 
 The system of distribution is similar to the ordi- 
 nary methods of wiring. A recess in the wall 
 should be provided for the reception of the main 
 and feeder line conduits exclusively, provided with 
 a detachable cover throughout ; or at a certain 
 point on each of the different flows, exactly as 
 shown in Fig. 2. 
 
 In the figure showing tubes in recess A repre- 
 
HOW TO "WIEE BUHDINGS. 
 
 39 
 
 Fig. 2. — Condttit Wiring. 
 
40 HOW TO WIKE BTTILDINOS. 
 
 sents the main tube. / B represents the main floor 
 cut-out, inserted in a floor main junction box, O 
 represents the floor mains which connect with the 
 lamp circuits. Usually the main wires are large, 
 which make it advisable to have the cover of the 
 recess detachable the whole length. The main 
 wires can be so arranged that a pair are run from 
 the dynamo switchboard direct to each floor, or 
 the system of distribution can be so arranged 
 that the wires can be looped in the conduit, from 
 floor to floor, thus relieving the conduit of the 
 strain due to the weight of heavy conduct- 
 ors. The connections can be made as shown in 
 Fig. 3. 
 
 In Fig. 3, A represents main floor boxes, one 
 on each floor, to which are connected the con- 
 duits for the main wires. The wires as seen are 
 cut at each floor, so that instead of starting 
 at A^ and drawing the wires through the 
 conduit to A^, it is only drawn from box to box, 
 and the conductor is made continuous at the cut- 
 out connection. Hence, if in the future it be- 
 comes necessary to withdraw the wire from the 
 conduit, between any of the floors, it can be 
 quickly and easily effected. B represents the main 
 feeder junction box with cut-out inserted, for 
 means of connection between the feeder and main 
 
HOW TO WISE BUILDINGS. 
 
 41 
 
 
 Fig. 3. — Condxtit Work. 
 
42 HOW TO WIEE BUILDINGS. 
 
 wires. As this wire will generally have a large 
 cross-section, it will be necessary to provide an 
 angle-box at G (which is at the bend where the 
 feeders assume a perpendicular position). The an- 
 gle-box obviates the necessity of elbows, and at the 
 same time performs the function of a "fishing 
 box." 
 
 The lamp circuits are divided in a similar man- 
 ner to that made use of in ordinary wiring. All the 
 •circuits are brought to a central or grouping point, 
 and the conduits terminate at the box enclosing 
 the cut-outs, as in the "Panel" or "Closet" 
 method. Judgment must be exercised in dividing 
 the circuits so that the run from outlet to outlet 
 will not be too long or will not contain many turns 
 or bends. 
 
 37. One of the most simple and satisfactory 
 methods of floor wiring in conduiting, is shown in 
 Fig. 4, which represents all the floor main lines of 
 conduits located in the corridor, and at a point near 
 the ceiling. A represents single branch junction 
 boxes, fltted with a branch cut-out, one of each be- 
 ing located opposite to the room, whose lamps it 
 controls. The lamp circuit is connected with it and 
 is looped from outlet to outlet as shown in Fig 5, 
 keeping each room on one independent circuit. 
 The mains for the section of rooms will be looped 
 
HOW TO WIRE BUILDINGS. 
 
 43 
 
44 
 
 HOW TO WIEE BUILDINGS. 
 
 ^/y/7///////////////////////Y///y//XA 
 
 VTZTTTTTTTZTTTTTTTZTP'TTTTTTZ.' 
 
HOW TO WIRE BUILDINGS. 45 
 
 in a similar manner from A to A, so tliat provision 
 is made for easy manipulation. B represents the 
 main cut-out, and junction-box for the section 
 tlirough which the floor main O connects with the 
 section main ; D represents an angle-box, for use 
 at the turn, and for making easy the insertion of 
 the main wires in conduit C. E represents the 
 main floor junction-box and cut-out. 
 
 By the use of this method, the pressure on the 
 wires can be equalized just as nicely as in the 
 "Panel" system. This method tends to shorten 
 the distances between feeding points, manipulation 
 is easier, and while the cost of material is not 
 increased, the amount of labor is considerably 
 decreased. 
 
 38. When the lighting is for general illumina- 
 tion purposes, that is, when the lamps are turned 
 on or off at the socket, as in office buildings, etc., 
 the lamp circuits can be installed in various man- 
 ners, as shown in Figs. 6 and 7. The advantages 
 obtained are, that should the wire in the cut-out 
 (cut-out link) fuse, it would only disconnect a por- 
 tion of lamps located in any one room. Also, it 
 will sometimes save material and time, by shorten- 
 ing the length of the circuits, and avoiding turns 
 and bends. 
 
 39. The joints must receive the same care as the 
 
46 
 
 HOW TO WIRE BUILDINGS. 
 
 
 ■5T 
 
 X 
 
 GaaPlpe 
 
 Toctit-oiif6esi\ 
 otit/ils/Ioar^ 
 
 
 X Z^fiaor Xj 
 
 n 
 
 Taeiuf-0ti/fit^\ 
 ontkiafloor. 
 
 fioorJ 
 
 
 JancUonfi^ 
 
 Fig. 6. — Conduit Work. 
 
HOW TO WIRE BUILDINGS. 
 
 47 
 
 [ 
 
 4 
 
 
 o 
 
 
 o 
 
 M 
 
 P=4 
 
 ^^^^^^^i^^^^^^^^!^^^^^^^^^^ 
 
 
48 HOW TO WIRE BUILDINGS. 
 
 joints on the wire, and the conduits should be 
 handled in a careful manner. In no case must a 
 hole or break in the conduit be patched. 
 
 Not only must the continuity of the conduit be 
 maintained throughout, but care must be taken to 
 maintain its circular form also. 
 
 In concluding this chapter it may be stated in 
 short, that the use of conduits afford the only safe, 
 reliable, and permanent method of wiring for elec- 
 tric lighting and kindred purposes. 
 
HOW TO WIRE BUILDINGS. 49 
 
 CHAPTER VIII. 
 
 Switchboards. 
 
 40. It is preferable to make a plan, to scale, 
 showing all tlie appliances it is intended to place on 
 the switchboard before constructing it, so that suffici- 
 ent space and insulation may be provided between 
 conductors of different, or even of the same polarity. 
 The appliances and conductors should be so ar- 
 ranged that, whether for renewals or repairs, the 
 different circuits can be disconnected without dis- 
 turbing the remaining circuits, and without jarring 
 or dislocating the board. The faceboard should 
 be constructed of materials that are fire and moist- 
 ure-proof, such as marble, slate, etc. 
 
 Sufficient space should be allowed between the 
 back of switchboard and the wall of the room for 
 purposes of inspection, repairs, etc., and also that 
 should the waM. be damp, the switchboard will be 
 free from contact, and will not have water accumu- 
 late on it. Theatrical and converter switchboards 
 should be provided with a covering either in the 
 form of a door, or a roll, similar to that of a roller- 
 top on a desk. 
 
50 HOW TO WIRE BUILDINGS. 
 
 41. All switches and cut-outs should be equipped 
 with a suitable name-plate, designating the partic- 
 ular circuit they control. The name-plate should 
 either be fastened on, or directly under, the ap- 
 pliance. In all switchboards, especially those used 
 in theatres, the switches, cut-outs and other ap- 
 pliances, such as regulators, etc., should be arranged 
 so that manipulations are quick and easy. Usually 
 the best plan is to place the switches in p^ope^ 
 order or sequence, such as 1st, 2d, 3d floors, etc., 
 or Parquet, Balcony, Gallery, etc., in theatres. 
 
 42. Dynamo switchboards should be so con- 
 structed that all the instruments are in plain sight, 
 and that the dynamo switches can be easily thrown 
 in or out, and should be located as near to the 
 machine as possible. 
 
 The location of the switchboards should be such, 
 that the plates or connecting parts on the appliances 
 will not corrode or oxidize, due to the surrounding 
 Conditions. 
 
HOW TO WIRE BUILDINGS. 51 
 
 CHAPTER IX. 
 
 Appliances and Connections. 
 
 43. All connections, on appliances wliicli form a 
 part of the circuit, should be kept clean and bright. 
 The stationary connection should be securely fast- 
 ened; the sliding or movable connections should have 
 sufficient surface, and bearing tension; and all metal 
 parts should have abundance of carrying capacity so 
 that undue heating will be obviated. The connec- 
 tions should be properly covered and protected. 
 All bases should be of porcelain, slate or similar 
 material, and all parts should be so arranged that 
 access is easy. Switches should preferably be con- 
 structed in such a manner that arcing or excessive 
 sparking at the connections is impossible. 
 
 44. In joining or splicing wires, care should be 
 taken to have the metal at the point clean where 
 the splice is to be made. The connection must be 
 firm and rigid, and thoroughly soldered and insu- 
 lated. The splice or joint must be made in such 
 manner that in swinging or bending the wire the 
 solder will not crack or become loosened. In chap- 
 ter Y was shown the relation of the resistance of 
 
62 HOW TO WIBE BUILDINGS. 
 
 the wire to the lamp circuit, and the amount of en- 
 ergy expended in same, but it was assumed that the 
 resistance was equally distributed along the line. 
 Should the line or conductor contain an improperly 
 made joint, that is, one that is loose or corroded, the 
 resistance at that point might exceed the amount of 
 resistance in all the rest of the line. The conse- 
 quence would be an abnormal heating at the joint, 
 which would gradually extend throughout the 
 whole length of the circuit; the current required for 
 the lamp would be consumed in generating 'heat, 
 the candle-power of the lamps would decrease, etc. 
 
 It is often the case that high grade wire is used, 
 and still the insulation resistance may test low. 
 Generally that is due to the careless manner in 
 which the joint was insulated. 
 
 The rule is to have the insulation at the joint or 
 splice equal to that originally on the conductor. 
 
HOW TO WIEE BUILDINGS. 53 
 
 CHAPTER X. 
 
 Converter Work. 
 
 45. The converter is practically an induction coil, 
 in wMch high, voltage and a small amount of cur- 
 rent are converted or transformed into low voltage 
 and a large amount of current. The general method 
 of constructing induction coils is : a spool having 
 for its core a bundle of fine iron wires ; a few lay- 
 ers of comparatively coarse wire are then wound 
 on the spool, and the ends turned out so that con- 
 nections with battery or source of current can be 
 made, over the coarse wire. Thoroughly insulated 
 from this are wound a large number of layers of 
 very fine wire, each layer carefully insulated from 
 the others. The coil nearest the core is the primary 
 coil, and the outer, coil of fine wire, is the second- 
 ary coil. When the primary coil is connected to a 
 few cells of battery, and the coil is equipped with 
 a rapid make and break device, a powerful electro- 
 motive force is created in the secondary coil. The 
 iron core is used for the purpose of increasing the 
 lines of force that pass through the coils, and is 
 composed of a number of fine wires, to avoid the 
 
64 • HOW TO WIEE BTTILDINGS. 
 
 waste or "Foucault" currents which would be 
 created in a solid core, and which tends to make 
 the coils act sluggishly. 
 
 46. In the case of the converter, the coils are 
 constructed in a manner directly opposite to that of 
 the ordinary induction coil. The converter primary 
 consists of a small wire and many layers, and the 
 secondary coil consists of a large wire with a few 
 layers. 
 
 The amount of current in amperes supplied to the 
 primary coil is small, but the voltage is high, and 
 the current in amperes created in the secondary 
 coil, is large, but the voltage is low. The size of 
 the coil governs the difference of potential and the 
 current produced, or, in other words, the fewer the 
 number of layers on the secondary, the greater the 
 current in amperes, and lower the voltage. 
 
 The converter as applied in practice, is one of the 
 most important discoveries appertaining to the art 
 of electric lighting, and is destined, at an early 
 date, to play an even more important part than it 
 does at present. It is therefore essential that wire- 
 men should familiarize themselves with the work- 
 ings and construction of the various types of con- 
 verters. They are usually located on the roofs, or 
 sides of houses, on poles, or in the vaults of struc- 
 tures where the underground system is used. 
 
HOW TO WIRE BUILDINGS. 
 
 55 
 
56 HOW TO WIRE BUILDINGS. 
 
 When placed outside of a structure, a double pole 
 switch and cut-out should be inserted in the line at 
 the point of entrance to the building. When the 
 converter is located in the vault or cellar, the pri- 
 mary wires should be thoroughly insulated and 
 protected from leaks, grounds, short circuits, and 
 mechanical interference or dislocation, and at no 
 point should the conductor, or the material sur- 
 rounding it, touch the structure. The greatest care 
 should be taken, at the point where the wires enter 
 the building, to exclude gases, moisture, etc. The 
 insulation directly on the conductor should be of 
 the highest grade. The- conductor should be in- 
 serted in a conduit composed of insulating mate- 
 rial, and all should be inserted in a galvanized iron, 
 or such like, pipe. The iron pipe should be fast- 
 ened to, but kept free from, the building by the 
 use of strong iron arms, having a band of insulating 
 material between them and the iron pipe as showu 
 in Fig. 1. The inner tube or insulating conduits 
 acts as a protection against the abrasion of the cov- 
 ering directly on the wire, and insulates it from 
 the outer iron pipe. It also admits of more free- 
 dom in handling the circuit. 
 
 A separate conduit and pipe should be provided 
 for each wire, and should extend to a box contain- 
 ing the main cut-out and switch. This box should 
 
HOW TO WIRE BUILDINGS. 57 
 
 be fire-proof and water-tight, and should be out of 
 contact with the walls of the structure. Sockets 
 should be provided for the entrance of the pipes, so 
 that the connection between them will be rigid and 
 tight. The box should be of ample size, fitted with 
 a cover or door, which should be kept locked, and 
 fitted with a panel of glass, so that inspection, 
 without exposure, is possible. It should be located 
 as near the point of entrance, and in as dry a 
 place as possible. 
 
 The converter should also be located as near to 
 the point of entrance as possible, and should be 
 enclosed in a box, which should be constructed of 
 fire-proof material. The box should be kept free 
 from contact with the building, in a manner similar 
 to the switch-box. It should completely enclose the 
 converter. The roof of the box should extend some- 
 what over the sides and act as a water shed, and 
 ventilating holes should be cut in the sides. In 
 short, all primary work, which is that part begin- 
 ning at the point of entrance, up to and including 
 the converters, must be kept free from contact with 
 the walls or floors of the building. 
 
 47. The distribution of current is essentially the 
 same as in low tension direct multiple arc systems, 
 and the total loss in the wires must not exceed two 
 per cent. The circuits can either be divided in 
 
S8 
 
 HOW TO WIRE BUILDINGS. 
 
HOW TO WIRE BUILDINGS. 59 
 
 accordance with the rated capacity of the converter 
 (providing a separate one for each circuit,) or, the 
 circuits can be brought to, and connected with 
 omnibus wires in the usual manner, and also the 
 secondary of each converter connected to the same, 
 in a manner similar to the connection of dynamos 
 in multiple as shown in Fig. 2. Where converters 
 are to be connected to wiring on the three- wire sys- 
 tem two converters are necessary. The primaries are 
 connected in the usu?il manner, but the secondaries 
 are connected in series. The two outer wires con- 
 nect, one on each terminal, and the middle or neu- 
 tral wires connect to the wire between the convert- 
 ers as shown in Pigs. 3 and 4. Where the larger 
 sized converters are used, they should be set on a 
 platform, built up and insulated from the floor ; 
 and the switchboard should be so arranged that 
 the primary work is separated from the secoiidary 
 work. It is preferable to- construct two switch- 
 boards, the backs_ facing each other. 
 
 In a large converter plant, and where the lighting 
 is such that the greater portion of lamps are in use 
 only at stated times, it is the most economical to 
 arrange the wiring and converters in such manner 
 that these particular lamp circuits, including the 
 converters for same, are only connected to the pri- 
 mary circuit at the time of use. The primary and 
 
60 
 
 HOW TO WIEE BUILDINGS. 
 
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 1^ 
 
62 HOW TO WIRE BUILDINGS. 
 
 secondary circuits of each converter should be pro- 
 vided with a double-poled cut-out and switch ; and 
 should more than one converter be connected, the 
 primary circuit should, in addition to those for each 
 converter, be provided with a main cut-out and 
 switch. 
 
 48. It is preferable, where converters are located 
 in a building, to have all cut-outs located outside 
 of the converter. 
 
 In no case must the two wires forming the pri- 
 mary circuit, be bared at the same time, and in 
 close proximity to each other. In splicing or in- 
 stalling work, only one wire at a time, should be 
 bared. Care must be taken in handling same*, so 
 that the body does not complete the circuit. 
 
HOW TO WIKE BUIIDINGS. 63 
 
 CHAPTER XI. 
 
 Overhead Wiring. 
 
 49. It is often necessary in isolated lighting to 
 connt^t the wires in more than one building to a 
 dynamo, which necessitates pole, or outside work. 
 If the distance between buildings is not great, the 
 best method would be to provide a separate line or 
 feeder for each, and the wires can be fastened to 
 the outside of, and suspended between, the build- 
 ings. 
 
 It is preferable to use the petticoated glass insu- 
 lators, instead of the ordinary porcelain knot, for 
 this style of work. They should be kept free from 
 contact with the building, and allowance must be 
 made for swinging, so that the wire will not strike 
 the building. They should be separated sufficient- 
 ly, i.e., in case of sag they will not come in contact 
 with each other. This also prevents the accumula- 
 tion of snow or ice. Where the wires enter or de- 
 part from a building, generally over a door or win- 
 dow, they must be protected by an extra covering, 
 such as an insulating tube, not only for the purpose 
 of separating and insulating them, but also to act 
 
64 HOW TO "WIEE BUILDINGS, 
 
 as a water shedder. The holes should be bored at 
 an angle, having the lower point toward the out- 
 side. 
 
 50. In work of this kind, it is preferable to keep 
 the two wires forming each circuit, next to each 
 other in the same manner as the circuits were in- 
 stalled in the interior, so that when the plant is 
 turned over to the customer, his man, in charge of 
 the work, will more easily understand the system 
 of wiring. The liability of mistakes, when making 
 changes, will be lessened. 
 
 51. In pole line work, the poles should be as 
 short as possible. In setting in the ground, the 
 depth is governed by the nature of soil, the height 
 of the poles, and the weight of the wire. Generally, 
 for a 30-foot pole, 4^ to 5 feet is sufficient. Should 
 the ground be swampy, a good plan is to excavate 
 widely and deeply, to admit placing a strong barrel 
 in the hole, into which the pole is set. The barrel 
 should be filled and packed with small stones and 
 sand, and the whole covered with the dirt. This 
 will form a suitable foandation should the poles be 
 short and the weight of the wire not abnormal. 
 The base of the pole should be about 8 inches 
 in diameter, and the pole should taper somewhat 
 towards the top. If the poles are to be longer than 
 
HOW TO WIEE BUILDINGS. 65 
 
 30 feet, a safe rule is to increase the diameter of 
 the pole 1 inch for every increase of 5 feet in 
 length, up to 40 feet ; and 2 inches in diameter for 
 every 5 feet increase in length thereafter. The dis- 
 tance between the poles must also be considered. 
 Chestnut wood is generally preferred, although 
 cedar and Norway pine poles result satisfactorily. 
 
 52. The cross-arms should be securely bolted to 
 the pole, and about 6 to 8 inches be allowed be- 
 tween wires. Care should be taken when fastening 
 the wires to the insulators, which should be of the 
 petticoateU pattern, so that the "tie wires" do not 
 cut the insulation on the wires. It is preferable to 
 provide an extra protecting cover for the wires at 
 all the insulators. 
 
 53. The wires should be arranged so that the same 
 wire will be fastened to the corresponding pins on 
 each pole, throughout its entire length. The dis- 
 tance between poles depends upon the weight and 
 size of the wire. A fair average distance would be 
 200 feet. 
 
66 HOW TO WIRE BUILDINGS. 
 
 CHAPTER XII. 
 
 FxTSE Wire. 
 
 54. The fuse wire is to an electric lighting system 
 or plant what the safety valve is to a system of 
 steam generation and supply. The wire for fuses 
 is composed of an alloy of tin, lead, etc., and to 
 properly perform its functions should never be con- 
 nected in a circuit carrying in amperes more or less 
 than the rated carrying capacity of the fuse wire. 
 That is : never use a 10-ampere fuse in a 5-ampere 
 circuit or vice versa. Never make any allowance in 
 the carrying capacity of the fuse wire. It has al- 
 ready been tested and standardized by the manu- 
 facturers. - 
 
 55. The fuse wires are connected in the circuit 
 by means of a cut-out block, and when grounds, 
 crosses, or excessive leakage occur, the current in- 
 creases to such an extent that the conductors be- 
 come unduly heated, due to their resistance. The 
 nature of the fuse wire being such that it will melt 
 at a lower temperature than the copper -wire, it will 
 in the event of an occurrence of this kind, melt, 
 thereby automatically opening or breaking the cir- 
 
HOW TO WIRE BUILDINGS. 67 
 
 cuit. If the fuse wire is too small, it will fuse un- 
 necessarily, which is a source of annoyance ; but 
 should the fuse wire be too large, it will only melt 
 after the load becomes too great, at which time the 
 line and dynamo are so hot that the insulation is 
 affected, or the resistance of the copper wire in case 
 of electrolytic action, will be greater than that of 
 the fuse wire (making allowance for the difference 
 of melting points), in which case the wire will melt 
 and may form an arc. In the event of an occur- 
 rence of a short circuit or heavy ground, if no pro- 
 vision in the shape of fuse wires had been made, 
 the line or armature would melt. 
 
 The importance of using only fuse wires, that are 
 stn.TidflTrlized- is eviflp.Tit. 
 
68 HOW TO WIEE BUILDINGS. 
 
 melt, but short-circuits is not the only element to 
 guard against. Leaks and grounds are just as liable 
 to occur, and the rating of the fuse wire must be in 
 accordance with these liabilities. To explain the 
 function of the fuse wire more clearly, it may be 
 said that if in a piping system for water, steam, 
 «tc., the pipes should be overloaded, they will 
 break or burst at the weakest point. In a wiring 
 system, instead of bursting, the conductor will melt 
 at the point which is weakest. To prevent this 
 happening in the dynamo and conductors, is the 
 function of the fuse wire. Its cross-section or car- 
 rying capacity, therefore, is figured only for the 
 current necessary for consumption in the lamps, 
 and should any increase occur, the wire will at 
 once melt and disconnect the circuit. The question 
 of fuse wires should also be considered from a 
 financial standpoint. Should they be too large, 
 and a ground occur, the dynamo is not only gener- 
 ating the current consumed by the lamps, but also 
 that which is wasted through the ground, and 
 should it be in a system in which the dynamo is 
 already heavily taxed, this additional amount 
 which is wasted, will cause an abnormal drop in 
 potential, or still worse, burn out the armature. 
 The only method, whose prompt action can be as- 
 sured, is the use of fuse wires, the capacity and 
 
HOW TO WIRE BUILDINGS. 69 
 
 fusibility of whicli has been carefully tested and 
 standardized. 
 
 57. The insertion of fuse wires in circuits, is of 
 too great importance to be a matter of chance or 
 guess-work, and wiremen should never use fuse 
 wire or links, other than that supplied by the par- 
 ticular company or contractor, in whose employ 
 they are at the time, because the distance between 
 the screws on the cut-outs may be greater or less 
 than for those used by other companies. This will 
 change the carrying capacity of the fuse wires. 
 Or, again, the alloy may be different. 
 
70 HOW TO WIRE BUILDINGS. 
 
 CHAPTER XIII. 
 
 iNSTJLATIOlSr. 
 
 58. Conductors are insulated for the purpose of 
 harnessing or controlling the current, so that it 
 can be directed in a certain defined path, which is 
 generally wire composed of copper. In addition to 
 its inability to transmit current, the insulation 
 should be absolutely moisture-proof, and, if possi- 
 ble, fire-proof. 
 
 Rubber, and compounds composed principally 
 of rubber, are, for practical purposes, the best. 
 Rubber is elastic, and can be bent without injury. 
 Being moisture-proof, it acts as a safeguard against 
 the worst element of trouble (see Electrolysis). 
 Although not fire-proof, it will withstand high 
 temperature without melting. This material being- 
 also naturally delicate, is protected and strength- 
 ened by an outside covering, which is generally 
 composed of fibrous material, treated chemically, 
 so that it becomes to a great extent fire-resisting. 
 The outer covering is not relied on for its insulating 
 qualities, but more, fro;fn a mechanical standpoint, 
 as a protection against abrasions, etc. Experience 
 
HOW TO "WIRE BUILDINGS. 71 
 
 and time lias demonstrated that, protection against 
 moisture, is a prevention of fire ; and the best re- 
 sults for interior work, have been obtained when 
 "the wires were insulated by a material similar to 
 "that mentioned. 
 
 59. To secure permanence, the quality of the in- 
 sulation must be of the best, and absolute contin- 
 uity must be maintained. The minutest crack, 
 bruise, or pin-hole is sure, sooner or later, to create 
 trouble. It must be handled with the utmost care, 
 and the small amount of extra time spent in care- 
 ful handling, will more than offset the time and 
 trouble that would be needed to locate and repair 
 insulation damaged by carelessness. The manu- 
 facture of high grade wire of this nature, appre- 
 ciating the importance of the subject, use the ut- 
 most care and vigilance in its manufacture. It is 
 one continual round of inspection and testing, from 
 the start to the finish. When the wires are made 
 up in coHs, they receive the final test, and if found 
 to be up to the standard, are made ready for market. 
 The same care is exercised in the packing and ship^ 
 ping, and if equal pains were taken after the Tvire 
 left the manufacturer's hands little trouble would 
 be experienced, due to defective insulalaon. The 
 greatest source of danger is the rough usage it 
 receives at the hauds oj inexperienced or careless 
 
72 HOW TO WIRE BUILDINGS. 
 
 wire-men. Another source of trouble is, insuffi,cient- 
 ly insulated joints or splices. When baring the 
 wire to make a joint, the insulation should not be 
 torn off, or cut in a manner similar to whittling 
 wood. It should be cut at right angles to, and 
 neatly severed from, the conductor, and then slit 
 open between the points cut. It will then be an 
 easy matter to remove the insulation, without strain- 
 ing it on either side of the exposed part. In solder- 
 ing, care should be taken to keep the insulation* 
 free from the acid and flame. 
 
 60. When the splice is made, it should be insu- 
 lated in a manner equal to that on any other part of 
 the line. This is usually accomplished by the use 
 of a strip of rubber compound, wound or wrapped 
 around the joint, starting at a short distance back 
 from the splice, and on the insulation. In wrap- 
 ping the tape it should be wound at an angle, so 
 that each of the layers will lap over one-half of the 
 preceding wraps. This provides a double thick- 
 ness. If the conditions are adverse, an extra wrap- 
 ping should be provided, and placed over the first, 
 in such a manner that the laps of the second cover- 
 ing cross the laps of the first. The heat of the 
 hand is generally sufficient to cause the material to 
 adhere and form a solid mass. Over all should be 
 placed a tape of linen or Such material, impregnated 
 
HOW TO WIRE BUILDINGS. 73 
 
 with rubber. When taping splices on exposed 
 lines in a perpendicular position, the wrapping- 
 should be started at the bottom of the splice and 
 worked towards the top. In this manner the tape 
 will act as a shedder. 
 
 61. In molding work, the grooves should be suffi- 
 ciently large to admit the wire easily, without being 
 forced in. When fastening wires to porcelain in- 
 sulators with tie wires, an extra wrapping of tape 
 should be put over the wires at those points, and 
 care taken, that the tie wires do not bruise or dis- 
 rupt the insulation. The more recent styles of por- 
 celain insulators obviate the use of tie wires, and 
 for this reason are a great improvement. Forcing 
 wires in or around sharp corners is not recom- 
 mended, and should be done with the greatest care. 
 
 When uncoiling wire, be careful not to get a sharp 
 kink in it. Should a defect in the insulation of a 
 coil of wire be discovered, the whole coil should 
 be put aside and subjected to a test before any part 
 is used. In new buildings especially, the greatest 
 care should be exercised. Avoid having the wire 
 either in coils, or strung out, lying on the floor, 
 while using. The floor is generally covered with 
 mortar, brick, and other sharp or rough materials ; 
 mechanics are constantly moving about, and the 
 fall of a brick, or a barrow wheeled over the wirCj 
 
74 HOW TO "WIRE BUILDINGS. 
 
 is generally all that is necessary to impair the in- 
 sulation. The defect may not show at the time, but 
 sooner or later it is bound to be the source of 
 trouble. When passing wires through walls, floors, 
 partitions, etc., a tube of insulating material should 
 first be inserted, so that there may be no danger of 
 tearing the insulation as it is passed through. 
 
 62. For pole line or outside work, a strong and 
 durable weather-proof covering should be placed 
 over the insulation. 
 
 The quality of insulation can only be determined 
 by tests, and practical application, but to form a fair 
 estimate of the quality simply by inspection, in a 
 general way, it may be said that: the insulation 
 should be tough and lively, that is, it should not 
 resemble leather in the quality of its toughness, but 
 should possess hiore elasticity, and when stretched 
 and suddenly released, it should quickly assume 
 its previous shape. If when pulled in opposite 
 directions, it parts without stretching, somewhat as 
 dry putty or dongh would, it is inferior. The best 
 grades have two layers of insulation, an inner white 
 or red, and an outer black, core, and an additional 
 covering of braid or tape over all. The advantage 
 of the special inner layer is the prevention of the 
 oxidization of the conductor ; and should the outer 
 layer become bruised or impaired, the wire is still 
 
HOW TO WIRE BUILDINGS. 75 
 
 protected by the inner layer. The best manner in 
 whicH to make the superficial tests, as explained, is 
 to cut a small strip of insulation from the wire, 
 divesting it of the tape or braid. 
 
 Another method of testing for toughness, is : 
 Taking a piece of No. 14 wire insulated, twist 
 and bend it, until either the wire or the insulation 
 is broken. 
 
 In a first-class insulated wire, the copper will 
 break, and the insulation will remain intact. 
 
76 HOW TO "WIRE BUILDINGS. 
 
 CHAPTER XIV. 
 
 Electrolysis. 
 
 63. In discussing this subject, it will be treated 
 only with a view of showing its relation to Electric 
 Light Wiring. While it is really a part of the 
 previous chapter, it was considered too vital to 
 be merely mentioned. It is of the utmost import- 
 ance that wiremen and others Interested in con- 
 struction work should be familiar with the subject. 
 
 Wires are also insulated for the purpose of pre- 
 venting electro-chemical action. The word "Elec- 
 trolysis" means Electrical analysis, or analyzing 
 with, or by, the use of electricity. All liquids, 
 with the exception of oils, are fair electrical con- 
 ductors, and under certain conditions even oil will 
 lose its insulating qualities to a great extent. 
 
 Insert the wires forming both sides of a battery 
 circuit, each into a glass tube, closed at one end 
 and nearly filled with water, invert same into a 
 larger jar, into which, water must also be poured. 
 The larger jar should be so arranged that the wires, 
 composed of platinum, will not come In contact 
 with the water in same ; the use of the platinum 
 
HOW TO WIRE BUILDINGS. 77 
 
 prevents oxidization of the terminals. In complet- 
 ing tlie circuit, through the water, decomposition 
 of the water ensues. Water being composed of 
 hydrogen and oxygen, it will in short be 
 found that these gases have been generated, the 
 hydrogen in one tube, and the oxygen in the other, 
 and in proportion to their relative quantities, The 
 separation or decomposition is caused by the ac- 
 tion of the current when flowing through the water. 
 Instead of using platinum wire and two tubes 
 and a jar, we will change the experiment somewhat. 
 We will take a jar filled with water into which are 
 placed the ends of two pieces of ordinary copper 
 wire, connected to battery. When the current is 
 turned on, the water completes the circuit.. In this 
 case not only is the water decomposed, but the 
 copper also. The wire forming the positive pole 
 will be decomposed and the atoms will be carried 
 through the water to the negative wire. This 
 action in electric lighting is sometimes termed a 
 "partial short-circuit," and if the resistance of the 
 conductor, either liquid or metallic, is lower than 
 that of the fuse wire, the latter will melt and so 
 disconnect the circuit. 
 
 64. The most common causes of electrolysis are, 
 defective insulation on the wire ; joints insufficient- 
 ly insulated, excessive and continuous moisture, 
 
78 HOW TO WIRE BUILDINGS. 
 
 etc. With insufficiently insulated wire located in 
 or fastened to a damp or moist wall, the amount of 
 current escaping or leaking may at first be very 
 small, but the action of the current, and the oxide 
 from the copper, in a short time render the insula- 
 tion absolutely worthless. The leak increases, and 
 the current flowing through the copper wires, which 
 are immersed in water, will create the chemical 
 actibn, as explained. The copper will be decom- 
 posed, and dissolves away into the water. Copper 
 oxidizes rapidly, and the wire at this point, will in 
 a short time be wholly decomposed. The greatei 
 the current and the lower the resistance of the 
 moisture, the quicker this will be accomplished. 
 
 Where this defect occurs, the action is as follows: 
 If the resistance of the moisture or liquid between 
 the poles, is as low as, or lower than, the resistance 
 of the fusible strip used in the cut-out, the result 
 will be the same as in a short-circuit ; that is, the 
 fuse will melt. But should the resistance of the 
 moisture be far greater than that of the fuse wire, 
 the decomposition of the wire will gradually be ac- 
 complished, and aa it advances, the heat, and loss 
 of electrical energy in the conductors increases, the 
 lights become dimmer, and the carrying capacity 
 of the wire decreases, to the point where it melts 
 instead of the fuse wire in the cut-out. 
 
HOW TO WIRE BUILDINGS, 
 
 79 
 
 In other instances, the wife will be so decomposed 
 and so thin that at a certain point it is as fine and 
 sharp as an ordinary needle, and a slight vibration 
 
 Figs. 1, 2 and 3. — Electrolysis. 
 
 of the building will cause the wire to part and an 
 arc to occur. 
 
 65. The foregoing proves the importance of prop- 
 erly fusing the circuits, and using only the best 
 e;rade of materials. The best and most effective 
 method of obviating the danger, is to use conduits, 
 and high grade moisture-proof wires throughout, 
 providing a separate tube for each wire, and ex- 
 cluding moisture at the joints, etc. 
 
80 . HOW TO WIRE BUILDINGS. 
 
 CHAPTER XV. 
 
 Adverse Wiring Conditions. 
 
 66. Where adverse, conditions exists, such as 
 moisture and gas, the best results have been ob- 
 tained by stringing the wires, fastened to suitable 
 insulators, on the face of the walls, etc. The in- 
 sulators should be as few as possible. The fixtures 
 and wires should be kept free from contact with 
 the building. The cut-outs and switches should be 
 located in a clean dry placCj and to accomplish this, 
 the length of the circuits must; if necessary, be in- 
 creased. The fixture, if one is necessary, should 
 consist of a metallic pipe, and the wiring of the 
 fixture must be two heavily insulated wires. The 
 end of the pipe toward the outlet should be closed 
 by a cork, putty, or insulating compound. The 
 socket and lamp should be enclosed in a water-tight 
 globe. Key sockets should never be used, but all 
 circuits be controlled by switches. The fixture 
 should from time to time, be treated to a coat of 
 preservative paint. 
 
 In fixtures placed on the outer walls of a build- 
 ing, the stem or pipe should extend through the 
 
HOW'TO "WIEE BUILDINGS. 81 
 
 entire thickiiessof the walls, and the electrical con- 
 nections be made in the interior of the building. 
 
 All shades on outside fixtures should be of the 
 hood pattern, and be provided with an inner shell 
 or cover, so that the socket and lamp connections 
 are protected from the elements. 
 
 67. If conduits are resorted to, the same general 
 directions must be followed, and care must be taken 
 to exclude moisture and gas from the interior of 
 the tubes. 
 
 Siables.— The chief trouble in stables is due to 
 the ammonia which is generated in the stalls. " The 
 moisture and exposure also affect not only the in- 
 sulation 'on the wires, but corrode all the metallic 
 parts of the fixture and the line appliances. There- 
 fore the' weakest points are at the joints,' sockets, 
 cut-outs and switches, and connection between the 
 fixture and circuit wires. 
 
 Breweries. — The conditions are somewhat similar 
 to those which exist in stables, and in some por- 
 tions of the structure, excessive moisture exists at 
 &11 times. " In other portions, the temperature is 
 extremely high, and in still other parts, very low 
 temperature exists. The same care must be taken, 
 as outlined in the general directions, and in the 
 fermenting room, if the conditions are unusually 
 severe, double petticoated glass insulators set on a 
 
82 HOW TO WIRE BUILDINGS. 
 
 bridge or collar, suspended from the ceiling should 
 be used, and the wires fastened thereto. The 
 bridge or collar should be treated to at least two 
 coats of preservative, insulating paint. The. fix- 
 ture wire should be of the same size as that on the 
 lamp circuit, and the lamp circuit should be con- 
 trolled by a switch and cut-out only, located in 
 some suitable place. For the mains and feeders, 
 conduits are recommended. If conduits are used 
 throughout, care must be taken to keep the interior 
 of the tufces free from moisture, gas, etc. 
 
 Oil Works, Etc. — If the conditions are such that 
 the oil does not leak through the floor excessively, 
 then a general observance of the succeeding direc- 
 tions is all that is necessary. In some cases the 
 buildings are of the ramshackle sort, and the oil 
 leaks freely through the floors. Where the leak- 
 age is thus excessive, the only safe method is to 
 provide a continuous sliedder, for the line and fix- 
 tures, consisting of tin, heavily coated with non- 
 corrosive paint. The hood or shedder should be 
 suspended from the ceiling, and the conductors be 
 kept free from contact with the building. 
 
 Where explosive gases are generated, or where 
 paints, naphtha, and such materials are used or 
 stored, tlie conductors sliould be kept free 'from 
 contact Avith the building, and be exposed as much, 
 
HOW TO WIRE BUILDINGS. 83 
 
 as possible, care being taken to provide against the 
 accumulation of gases, etc., at any point. The 
 fixture wire must be connected directly to the 
 lamp-circuit wires, omitting the cut-out. All the 
 circuits must be controlled by a double-pole cut-out 
 and switch only, and the same must be located 
 where the conditions are most favorable. 
 
 68. In all such cases as those mentioned, the use 
 of conduits on the mains and feeders is recom- 
 mended. In no case must wires be moulded or 
 cleated. Either large porcelain , knobs or glass 
 insulators must be used. 
 
 Insulated wires, of any sort, must never be im- 
 bedded directly in plaster ; and where alkalies, or 
 acids exist, an extra covering, such as conduit, 
 must be provided. 
 
 Avoid placing wires ynder tiled floors, etc. 
 Floors of this kind are usually cleaned with sul- 
 phuric acid, which being absorbed by the tile and 
 cement, attacks the insulation. 
 
 In prisons, asylums, etc., the wires, lamps and 
 appliances must be inaccessible for the inmates, 
 but the switches and cut-outs must be located in a 
 place easy of access for those in charge. AU the 
 cut-outs and switches contfolling particular circuits 
 on the different floors should be located in a place 
 and manner corresponding to the conditions on the 
 
84 HOW TO WIRE BUILDINGS. 
 
 other floors. This will tend to simplify matters, 
 and will not confuse the attendant, when it is 
 necessary for some reason to turn on the .lights 
 quickly. 
 
HOW TO "WIRE BUILDINGS. 85 
 
 CHAPTER XVI. 
 
 Theatre akd Stage Lighting. 
 
 69. In theatre wiring, the wires, cut-outs and 
 switches should be located in places out of the 
 reach of inexperienced or malicious- persons, but at 
 the same time of easy access to those having charge. 
 The cut-outs and switches should be grouped in as 
 few places as possible, so that the turning on or off 
 of lights may be quickly accomplished. All the 
 lights in the theatre proper and stage should be 
 controlled by switches at the stage switchboard. 
 The circuits controlling lights in the dressing- 
 rooms, cellar, and such places^ should also ramify 
 or branch out at this point. 
 
 The public lights, that is : the lights on the side- 
 walk, entrances, lobbies, foyers, waiting-rooms, 
 etc., should be connected to switches, aU at one 
 point, and controlled from the front of the house, 
 usually in or near the ticket office, or foyer. These 
 circuits should be connected with a separate feeder 
 direct itom the source of supply, and independent 
 of the circuits for the lights in the theatre proper. 
 
86 HOW TO WIRE BtriLDINGS. 
 
 70. The lights in the auaitorium are located in 
 the dome ; proscenium arch ; side-lights in the gal- 
 lery, balcony, and parquet, and in the private 
 boxes ; the front of, or face of the gallery ; bal- 
 cony and boxes ; and On the stage. All the circuits 
 for these lights, except the stage lights, are gen- 
 erally connected to the same regulator. 
 
 The lights for the orchestra or band, are placed 
 ill deep metal shades, painted greeil on the outside, 
 and white on the inner surface, so that when the 
 lights throughout the house are turned down, or 
 dimmed, the glare of • the music lights will not 
 counteract the effect. They must be arranged, so 
 that the light is reflected on the music only. The 
 method of distribution is generally as follows : 
 Separate feeders, extending from the switchboard 
 on the stage, are carried to the centre of each cir- 
 cuit, at which point the feeder terminates into a* 
 double branch Cut-out, and the lamp-circuit wires 
 are carried to the different lamps on the circuit. 
 
 A good plan is to provide a separate circuit, cour 
 necting with a switch and cut-out at the stage 
 switch-board with the : 
 
 Gallery side lights. 
 
 Balcony side lights. 
 
 Parquet side lights. 
 
 Gallery "face" lights. 
 
HOW TO WIRE BUILDINGS. 87 
 
 Balcony -'face" lights. 
 
 Private box lights, outside of dome lights, gen- 
 erally two circuits ; proscenium arch lights, two cir- 
 cuits. If, in addition to the side lights in the 
 house, chandelier or ceiling lights are placed in the 
 rear of each, a separate circuit for each floor should 
 be provided, and run similarly to the side light 
 circuit. 
 
 71. The rate of loss in the conductors is usually 
 computed at 5 per cent., and divided as follows : 
 1 per cent, loss in the lamp circuit, 1^ per cent, loss 
 in the feeder from stage switch board to the centre 
 of distribution of lamp circuit, and 2i per cent, loss 
 in the feeders from the dynamo-room or other 
 source of supply. The stage lights generally con- 
 sist of the foot, borders, bunch, entrance, ground, 
 projecting, and such other lights as may be used 
 for scenic or other effects; and a few "working" 
 lights. 
 
 7^. The foot lights generally consist of three cir- 
 cuits, provided with the plain red and greien, or 
 blue glass bulbs, respectively. The position and 
 construction of the fixture or reflector, and the 
 lamps, should be such that the lamps are out of the 
 line of sight,^ and the reflector so placed that the 
 view from the auditorium will' be wholly unob- 
 
88 
 
 HOW TO WIRE BUILDINGS. 
 
 structed. The lamp should be placed close to tlie 
 reflector, and in such a manner that the light is 
 reflected on the stage. In addition to the electric 
 lights, provision is made for gas lighting, and 
 as the space is limited, the work should be so 
 arranged, that in the event of the gas being lighted, 
 the excessive heat will not affect the electric work. 
 A satisfactory method is to construct the foot lights 
 in a manner similar to that shown in Fig. 1. The 
 
 lamp 
 
 Socket - 
 MouMiiig 
 
 Timber- —I 
 
 Staffeftoor 
 
 I34i ^(^asPipe 
 
 Fig. 1. — Theatre Lighting. 
 
 work is located under the stage, where dislocation 
 is improbable, and is securely fastened so that only 
 the bulbs of the lamps are visible. The work is 
 covered and protected by heavy sheet tin, and holes 
 are cut to correspond with the entrance of the 
 sockets. 
 
 This method will allow of placing a large number 
 of lamps in one row. The three circuits are so 
 arranged that the colors will alternate. 
 
HOW TO WIRE BUILDINGS. 89 
 
 Another method is, placing the wires on the out- 
 side of the reflector, having a frame work of wood, 
 and placing the lamps at an angle, as shown in 
 Fig. 2, These circuits are connected to the regu- 
 
 Staffefioor 
 
 Pig. 2.— Theatre Lighting. 
 
 lating device, either separately, or arranged so that 
 one regulator can be used for either, and the num- 
 ber is governed by the width Of the . opening — 
 usually as many as can be placed without crowd- 
 ing. The inner surface of the foot light reflector 
 should be coated with either white paint or lime. 
 
 73 Border lights are rows of lights located in a 
 reflector, and suspended between the curtains in 
 the " flies," and high enough to be out of the sight 
 of the audience; they are used for lighting the 
 body and back of the stage, scenes, etc. The 
 reflector is formed to throw the light in the direction 
 mentioned, and also prevents the light-giving 
 medium from being seen in the front of the house. 
 
L 
 
 90 HOW TO WIRE BUILDINGS, 
 
 Each border usually consists of one'row of plain 
 glass bulbs, and the number of rows and lamps on 
 each is governed by the width and depth of the 
 stage, and the number of side entrances. Usually 
 five rows are employed, and the two front, and the 
 three rear borders are connected to separate regu- 
 lators. At the opening, or front of the reflector is 
 placed a wire screen, to protect the lamps and also 
 acts as a fender in dropping or . raising curtains. 
 Each border consists of one or two separate cir- 
 cuits, and the fixture is connected to the feeder by 
 means of flexible cables, the ends of which termi- 
 nate in. connecting plates in the form of a plug, 
 which corresponds with a receptacle in the con- 
 necting block, fo which the wires from the switch- 
 board Tare '^connected. Where two circuits are 
 required, the lamps are connected alternately. 
 
 74. Bunch and entrance lights are used for light< 
 ingthe entrance, or for lighting a particular part 
 of the stage, when the remainder of it is in dark- 
 ness, etc., and also for general illumination. 
 
 The bunch lamps are usually placed on an iron 
 fixture, arranged so that they can be3 raised or 
 lowered or turned in any direction. The' entrance 
 lights arelusually lamps placed on a strip of wood 
 in the shape of a row of lights. The connections to 
 the_circuit are similar to those of the border lights, 
 
HOW TO WIRE BUILDINGS. , 91 
 
 a receptacle for connections in the floor being 
 provided on each side of the stage and at each 
 entrance. These pockets or floor receptacles must 
 be fitted in such manner that moisture is excluded, 
 and constructed of fire-resisting material. 
 
 The circuit from the switchboard is located on 
 the ceiling under the stage, and is not connected 
 CO a regulator. 
 
 75. Ground lights or rows, are constructed in a 
 manner similar to the entrance rows, and are used 
 for illuminating the back of hedges, water-falls, 
 platforms, balconies, etc., in the scenery, and are 
 laid upon the floor of the stage, at the point to be 
 illuminated. The receptacles used for the bunch 
 lights are made use of for these. All the stage 
 fixtures are portable, and the arrangements for 
 connecting ana disconnecting must admit of being 
 quickly accomplished. 
 
 76. Projection lights are used for special pur- 
 poses, such as throwing a beam of light in the 
 shape of a streak of lightning across the stage, or 
 directing it on a person, or object, or to suggest 
 moving water, etc. The projection light consists of 
 an arc light and suitable resistances, and is specially 
 designed for this class of Avork. The wires from 
 same can be connected with the incandescent wiring 
 
92 HOW TO WIBE BUILDINGS. 
 
 system used in the theatre. The lamp is provided 
 with screens, lens, Light filters, etc., and special 
 appurtenances for lightning effects. The fixture is 
 portable and the reflecting portion is arranged so 
 that it can be turned in any direction, or raised or 
 lowered. The flexible cable, used for connecting 
 the lamp with the system, is similar to that used 
 for border and bunch lights. The connections and 
 locations are temporary, as the lamp is carried 
 from one point to another according to its uses. 
 
 There is, however, a permanent line or circuit, 
 carried from the stage switchboard to a connecting 
 hlock, located in the front of the gallery. A pro- 
 jecting lamp is used at this point to throw light of 
 different colors on the ballet, or other quickly 
 moving objects on the stage. 
 
 77. In addition to the lights mentioned, others 
 of a temporary character, are used for special pur- 
 poses, SUCH as chandeliers, newel posts, candelabra, 
 hearth, moon, sun, etc. The fixtures for thei first 
 three are constructed of wood. The hearth lights 
 represent a fire in the grate, etc., and are usually 
 ordinary white glass lamps, placed in a receptacle 
 representing a grate, and the grate is covered with 
 red paper or mica.. The fixture which represents 
 the moon or sun, is constructed ordinarily ol wood, 
 in cylindrical form, a circuit of red and a circuit of 
 
HOW TO WIRE BUILDINGS. 93 
 
 ordinary lamps are placed therein, and the face of 
 the cylinder is generally of tinted glass, sometimes 
 formed and marked to represent the object. Each 
 circuit is connected with a toning device, so that 
 any tint may be obtained. By the use of the ton- 
 ing device, representations of setting sun or rising 
 moon will be faithfully borne out. The lamps must 
 be located at a distance from the face or glass, so 
 that spots of light or the shape of the carbon will 
 not show. 
 
 Nearly all the materials used on the stage for 
 theatrical purposes are flimsy and highly inflam- 
 mable, and the conditions are such, that a fire once 
 started will gain rapid headway. The work of the 
 stage hands in setting scenes, etc., is done in a 
 hasty manner. It is therefore necessary to provide 
 materials and to locate them in such ajnanner that 
 they will withstand the existing conditions ; and 
 care should be taken in fastening permanent cir- 
 cuits, that they are not on temporary structures, 
 liable to change. 
 
 The switchboard should be constructed, as far as 
 possible, of fire-proof materials, and the whole 
 should have a covering similar to the flexible roller 
 top used on desks, lined with asbestos, etc., so that 
 when the switcnboard is not in service, it prevents 
 interference with appliances, and also acts as a 
 
94 HOW TO WIRE BUILDINGS. 
 
 safeguard against falling objects, water, etc. The 
 switches, cut-outs and regula,tors should be pro- 
 vided with a suitable name plate, and be so located 
 on the board that connections with the lamp cir- 
 cuits can easily be made to provide for the various 
 combinations necessary in this class of work. At 
 the top of the board should be placed a pilot lamp, 
 from each circuit, to act as a guide for lighting or 
 toning purposes. 
 
HOW TO WIEE BUILDINGS. 96 
 
 CHAPTER XVII. 
 
 Plans of Distribution. 
 
 78. All circuits should be so distributed and con- 
 nected throughout a structure that practically the 
 pressure or difference of potential will be the same. 
 It is often the case that the total amount of loss is 
 small, but incorrectly divided ; that is, the greater 
 part is allowed in the lamp circuit or sub-feeder, 
 when it ought to have been allowed in the mains or 
 feeder, or vice versa. 
 
 Assuming 5 per cent, to be allowed in the con- 
 ductors, it is generally best to distribute the loss as 
 follows : 1 per cent, in the lamp circuit, 1^ percent, 
 in the mains, and 21 per cent, in the feeders. 
 
 The chance of having all the lamps on any one 
 lamp circuit in use is greater than the chance of 
 having all the lamps connected to a main in use ; 
 and a small loss in the lamp circuit, will allow of 
 placing a few additional lamps on those circuits 
 without appreciably affecting the whole wiring 
 system. The method of distribution is governed 
 by the manner in which the lamps are to be used. 
 In some instances, the lights are in use continuously; 
 
90 HOW TO WIRE BCriLDIKGS. 
 
 in others a certain proportion are in use at any 
 one time, and in still others, certain sections are 
 used at stated times. The distribution is therefore 
 •guided by these conditions. The best results are 
 secured when a separate feeder is provided, for the 
 separate sections having different conditions of 
 lighting. 
 
 79. All diagrams given here will show only one 
 wire, unless otherwise mentioned, and may be used 
 for the 2 or 3 wire system. 
 
 Fig. 1 represents a cut oat box, either in a iDanel 
 or closet located in the centre of its lighting area, 
 and shows the connection therewith of the floor 
 mains, which are connected with the vertical mains. 
 
 Fig. 2 represents a main and feeder, and more 
 particularly the various methods of distributing 
 from the mains to the different ramifying points or 
 panels.^ A represents the feeder from the switch- 
 board in the dynamo room, connecting with the 
 mains B at the point X, which is, in this case, the 
 main central point of lighting ; and the lamps are 
 figured as being at a distance equal to that between 
 the switchboard and X. B and D represent the 
 Vertical mains, and if the lights are evenly divided 
 on each floor, the distance is equal to one-quarter 
 the total length, B and D connect with floor mains 
 at each floor. On the 4th floor jlifand J[/" represent 
 
HOW TO WIRE BUILDINGS. 
 
 97 
 
 m-^JUi, 
 
08 HOW TO WIRE BUIL0INOS. 
 
 the floor mains connecting with the cnt-outs of the 
 lamp circuits. On the 3d floor, to equalize the 
 pressure, on account of two distributing points, the 
 floor mains are again divided, as shown. On the 
 second floor -S' and S' each represent a floor main, 
 and are necessary to equalize the pressure on ac- 
 count of the difference in the number of lights at 
 each box, and the distance, the box 2/' being quite 
 close to the feeding point. 
 
 On the 1st floor is shown a method which should 
 be avoided, because it is impossible to equalize the 
 pressure. If the pressure at the lamps from box y' 
 is normal, the pressure at the lamps from box y 
 and 2/' would be above normal, and,, on the otheK 
 hand, if the jiressure at the lamps from y is normal 
 that at the lamps from box y' and y^ would be 
 below normal. We therefore have a choice of two 
 evils, running the majority of lamps below their 
 rated candle-power, or, increasing the pressure, and 
 lamp breakage. 
 
 Fig. 3 represents a main and feeder system some- 
 what similar to that shown in Fig. 2, except that 
 the floors are greater in number. F represents the 
 main feeder, connecting with the sub-feeders i^' and 
 J*" at the point A. i^' and F' extend from A, and 
 connect with the main feeders c at the points D 
 and F. M represents the floor mains connecting 
 
HOW TO WTEE BUILDINGS, 
 
 i 
 
 yg -^ 'n ^ ^^ 
 
 ly 
 
 jr 
 
 ■O 
 
 
 J!/ 
 
 Q\ 
 
 ^Jt^ Mt 
 
 yj yx yr y 
 
 r* y-^ y 
 
 Pig. 2.— Plans Of Distribution. 
 
100 HOW TO WIRE BUILDINGS. 
 
 with the lamp circuits. In large buildings the 
 feeder systems, as shown in Figs. 2 and 3, can be 
 provided; for each side of the building. 
 
 Fig. 4 represents a plan of floor lighting, used in 
 factory or general exposed work. A represents the 
 main feeder, connecting with the sub-feeders B and 
 B'; at the point T the sub-feeders connect with 
 the main wires C and C" at the point JT, wliich in 
 turn connects with the lamp circuits L. Fig. 5, 
 represents a system of distribution somewhat 
 similar to that shown in Fig. 4. In Fig. 5 the 
 wires forming both sides of the, circuits are 
 shown. This method is made use of where all the 
 lights on any circuit are used at the same time, and 
 are turned on or off by means of switches. This 
 method can be applied when lighting large spaces, 
 such as sheds, depots, etc. A represents a main 
 feeder forming one side of the circuit, and its car- 
 rying capacity is computed at the total number of 
 'lights, and connects at B with AA, which is the 
 main wire forming one side of. the circuit and con- 
 nects with the wire forming that side of the lamp 
 circuit on each circuit at the point E. S and S^ 
 represent the wires forming each side of the lamp 
 circuit. C" C" C" C* are divisional mains forming 
 one side of the feeder circuit and connecting withi 
 S^ at tlie points K. It will be seeii that the feeder 
 
HOW TO WIEE BUILDINGS. 
 
 101 
 
 Fig. 3.— Plans of Distribution. 
 
102 
 
 HOW TO WIEE BUILDINGS. 
 
 L 
 
 X 
 
 I 
 
 l 
 
 C 
 L 
 
 I 
 
 I 
 
 Y 
 
 B' 
 A 
 
 L L 
 A 
 
 B 
 
 L 
 
 L 
 L 
 
 C 
 L 
 
 L 
 
 C 
 
 L 
 
HOW TO W^IRE BUILDINGS 103 
 
 A, and mains AA and the lamp wires S, form one 
 side of the entire circuit, A and A A being common 
 carriers to all.- On the other side of the circuit J3^ 
 forms one side of each lamp circuit independent of 
 each other, and the feeders marked 0" C O' O* are 
 connected to S^ and also independent Of each other. 
 At the terminals of the feeders are placed single 
 pole switches, by means of which any of the cir- 
 cuits can be connected without aflfecting the other. 
 
 Fig. 6 represents a system somewhat similar 
 to that shown in Pig. 5, except that in Pig. 5 
 the feeders were connected at the centre of the 
 length of the mains. In this case, sub-feeders 
 are necessary, due to .increased length, so that the 
 pressure at the point X in the mains would equal 
 that at the point JT. The method of connecting 
 the lamps, or throwing them in or out of circuit, 
 is the same as explained in Fig. 5. 
 
 Fig. 7 is somewhat similar to Figs. 4 and 5, 
 except in this case two separate feeders are pro- 
 vided for the purpose of equalizing the pressure, 
 and forming two. separate circuits of each, row of 
 lamps, each circuit being independent of the other, 
 on the same row, and also of those on the other 
 row. One side of the lamp circuit wire is dis- 
 connected at the middle, and each half is fed or 
 connected to a separate divisional feeder. The 
 
104 
 
 HOW TO WIEE BUILDINGS. 
 
 C*C3(?i 
 
 Fig. 5. — Plans of DisTRiBUTioiir. 
 
HOW TO WIRE BUIIiDINOS. 
 
 106 
 
 ? 
 
 444 
 
 ?' 
 
 e* 
 
 c^ 
 
 EAA 
 
 f 
 
 A 
 
 CS 
 
 444 
 
 r 
 
 c 
 
 i£ 
 
 C 
 
 Fig 6. — Plans of Distribution. 
 
106 HOW TO WIRE BUILDINGS. 
 
 method of throwing in or out of circuit by switches 
 is similar to that as described in Fig. 4. 
 
 Fig. 8 represents a system of distribution ap- 
 plicable to large isolated plants, and by a few 
 alterations in the method can be used for central 
 station distribution. (The diagram shows a "flat" 
 plan). In large hotels the lighting conditions are 
 constantly varying ; that is, all the lights in one 
 section of the building may be in use at one time, 
 and most of those connected on the feeders in the 
 other sections not in use, and vice versa. Consei- 
 quently the pressure on the wires is undergoing 
 variations constantly, the result of which would be 
 excessive lamp breakage, unsatisfactory service, 
 etc. Under certain conditions it is not practical to 
 wire at a low rate of loss, on account of the im- 
 mense increase in first cost. The interest oh the 
 investment will more than offset the small addi- 
 tional cost of pressure equalizers and the lost 
 energy in same. 
 
 Therefore, wh^n the conditions exist as stated, 
 the conductors are installed at a higher rate of losS. 
 In the diagram, F' to F'' represent the vertical 
 feeders, connecting to the mains and floor mains, 
 in the different sections of the building. The dia- 
 gram also shows the different mettiods of feeding, 
 which can be employed in each section. K repre- 
 
HOW TO WIRE BUILDINGS. 
 
 107 
 
 y' 
 
 /" 
 
 r^ 
 
 y 
 
 
 y' 
 
 t 
 
 
 r^ 
 
 y 
 
 Fig. 7.— Plans of DiSTRXBUTioir. 
 
 rx 
 
108 HOW TO WIRE BUILDINGS. 
 
 sents a " crib" to which all the different sectional 
 feeders .connect. E to E represent main feeders 
 connecting to the "crib" and extending to the 
 dynamo switchboard. On the wire forming one 
 side of each is connected a pressure equalizer, con- 
 necting with "the crib at the point where the main 
 feeders connect; and, extended to the dynamo 
 room switchboard, are run a pair of wires for each 
 feeder, which are connecting with a pressure indi- 
 cator. As the pressure varies at any of the feeder 
 points on the " crib," the same will be indicated on 
 the instrument and by throwing coils of the equal- 
 izer, out or in, the pressure can be, maintained at a 
 certain point. 
 
 Fig. 9 shows the method of connection, at 
 the switchboard, with the dynamo and feeders. 
 A and AA represent "Bus." wires which act as the 
 main or trunk line. Connected to this, are the 
 different main feeders, and the leads from the 
 dynamos. A pressure indicator is connected with 
 the "Bus," lines, to indicate the pressure in that 
 part of the wiring installation. On the positive 
 dynamo lead is placed an ampere-meter. 
 
 The negative wires of the feeder circuits are con- 
 nected to the "Bus." bar A. The positive feeder 
 wire terminates and connects to the faceboard of 
 the equalizer, and from another connection on the 
 
HOW TO "VVIBE BUILDINGS. 109 
 
 F^ 
 
 ^ 
 
 f^ 
 
 jre 
 
 /¥ pa 
 
 r7 
 
 % 
 
 
 ^^^ 
 
 \ 
 
 
 F9 
 
 E' E' E» E* 
 
 Fig. 8. — Plans of Distribution. 
 
110 
 
 HOW TO WIEE BUILDINGS. 
 
 I 
 
 %5 
 
 I 
 
 -I rrn 
 
 5. 
 
 ^ 
 
 5.i 
 
 ^3 
 
 «5 
 
 ?i 
 
 8q o 
 
 P-H 
 
 E-i 
 0} 
 
 O 
 09 
 
 <) 
 
 Ph 
 
 d 
 
 
HOW TO WIKE BUILDINGS. 
 
 Ill 
 
 ■equalizer faceboard', and connecting with AA ot 
 the " Bus." bar, is run another wire, equal in cross- 
 section to that of the feeder. The 'equalizer and 
 pressure indicator of each feeder circuit should be 
 placed directly ovei each other, so that when 
 throwing coils in or out of the circuit, the effect 
 can be noticed, It will also tend to simplify mat- 
 ters. 
 
 kf 
 
 ^ 
 
 ii9/. 
 
 
 Fig. 10. 
 
 WW 
 Plans of Distribution. 
 
 Fig. 10 represents the coils and method of con- 
 nections, in the equalizer, and to the feeder, and 
 "Bus" bar or wires on the dynamo switchboard. 
 
112 HOW TO WIRE BUILDINGS. 
 
 Assuming each coil to have a resistance of 1 ohm, 
 and that there were 10 coils, it Avill, from the con- 
 nections,, readily be seen how the resistance can be 
 varied. 
 
HOW TO WIRE BUILDINGS. 113 
 
 CHAPTER XVIII, 
 
 Distribution of Light. 
 
 80. In locating lamps, they should be so dis- 
 tributed, that each lamp performs its equal share 
 of the lighting, and is so located that, if the 
 candle power of each lamp is the same, the 
 diffusion of light will be equal, and if the number 
 of lamps is sufficient, a space can be illuminated 
 in such manner that the light is practically equal 
 throughout, 
 
 The number of lamps is governed by the space 
 to be lighted, the purpose for which the structure 
 is used, etc. 
 
 The practical unit of light is the 16 candle-power 
 lamp, and for ordinary illumination, one 16 candle- 
 power lamp for every 100 square feet, suspended 
 about 8 feet from the floor, is allowed. By 100 
 square feet is meant a space 10 ft. x 10 ft., or 
 8 ft. X 12 ft., etc. The amount of light, on this 
 basis, is allowed only when the conditions are such 
 that ordinary illumination is required, as in sheds, 
 depots, walks, etc., and where close inspection of 
 materials, etc., is not necessary. In waiting-rooms, 
 
114 
 
 HOW TO WIRE BUILDINGS. 
 
 ferry houses, etc., the. alio wailce is generally one 
 16 candle-power lamp to every 75 square leet. In 
 stores, offices, etc., for ordinary lighting purposes, 
 60 square feet is the usual allowance. 
 
 81. Fig. 1 represents the ideal method of dis- 
 tribution, but in practice is objectionable, where 
 pendants from the ceiling are used When the 
 lamps are located close to the ceiling and a fixture 
 
 to' JO' JO' JO < JO' > 
 
 >: 
 
 % 
 
 >: 
 
 H^ 
 
 ,^' 
 
 ^^ 
 
 >: 
 
 >: 
 
 >: 
 
 Ht 
 
 > 
 
 >' 
 
 :-4^' 
 
 7T- 
 
 Tt^ 
 
 ,4^ 
 
 
 V:^ 
 
 V / 
 
 y. 
 
 y. 
 
 Af- 
 
 X 
 
 \ (^ .'' 
 
 S'^t^'s' 
 
 X 
 
 y 
 
 H^. 
 
 ■y 
 
 X 
 
 Fig. 1.— Distribution of Light. 
 
 or finish, corresponding to the surroundings, -is 
 made, the sfEect is very good. In the diagram, 
 assuming the space to be lighted is 50 ft. x 50 ft. , 
 
HOiV TO WIRE BUILDINGS. 
 
 115 
 
 and th.e candle-power of the lamp is 16, to find the 
 number of lamps necessary, 50x50 = 2500 ft -^ 100 = 
 25 — 16 candle-power lamps. Dividing the ceiling in 
 squares of 100 ft. or 10 x 10 and placing a lamp in 
 the centre of the square, each light will have the 
 same amount of space to light, and the lamps will 
 "be an equal distance from each other. 
 
 If in the same space, it is intended to place two 
 lamps in a cluster, to obtain an even diffusion it is 
 
 12' e: 
 
 J2'S' 
 
 J2 6" < J2'6' 
 
 X 
 
 
 Y 
 
 / <• \ 
 
 
 
 -. / 
 
 A 
 
 
 / 
 
 
 x 
 
 ? 
 
 
 
 N f 
 
 X 
 
 
 Fig. 2. — Distribittion of Light. 
 necessary to use 32 lamps instead of 25 as in the 
 •first case. 
 
U6 
 
 HOW" TO AVIRE BUILDINGS. 
 
 Fig. 3 shows a method of distributioli, each out- 
 let having a cluster of four lamps instead of single, 
 lamps. 
 
 
 16- S" 
 
 f&'S" 
 
 /0'S' > 
 
 
 \ / 
 
 \ / 
 X / 
 
 
 \ 06 / 
 5 y 
 
 5; 
 
 X r 
 
 \ 
 
 A 
 
 / \ 
 
 \ / 
 
 5! 
 
 V 
 
 X /■ 
 
 N / 
 
 \ /' 
 
 X X 
 
 A 
 
 y X 
 
 * \ 
 / X 
 
 \ 
 
 Fig. 3. — Distribution of Light. 
 
 Dividing the lamps into clusters, requires more 
 lamps for the same space, and the greater the 
 number of lights at any one point, the more uneven, 
 will the lighting effect be. 
 
 82. Lighting from the side wall is not as econom- 
 ical as from the ceiling, and the results are limited. 
 Ordinarily side lights are only used to equalize the 
 diffusion of light, when the lighting from chande- 
 
HOW TO WIRE BUILDINGS. lit 
 
 liers, or in, a small room, and where a fixture from 
 the ceiling will impart a crowded appearance. For 
 the same reason, it is undesirable to place two 
 chandeliers in the same room. In still other in- 
 stances the chandeliers would obstruct the view, 
 and the lights would be in the line of sight. The 
 best results, where reflectors are used, are obtai led 
 by placing the bulb lengthwise, or parallel with 
 the reflector ; and by placing the lamp near to the 
 surface of the reflector, the reflecting power is in- 
 creased. When placing shades or globes over the 
 lamps, allowance must be made in the amount of 
 light, as a large quantity is absorbed, according to 
 the shape, color, and proximity to the lamp. The 
 surrounding, or prevailing color, of the walls, etc. , 
 must also be considered in the location and number 
 of lamps. Where shadows are created, due to 
 pilasters, etc. (where the light is evenly diffused 
 there wiU be no shadows), to overcome the shadows, 
 locate some lamps on the side of the pilaster, on 
 which the shadow is thrown, or a circle of lights 
 around the pilaster. This will remedy the defect. 
 
 83. Lighting by electricity, on account of the 
 absence of extreme heat, admits more artistic 
 display, than does any other artificial illumination. 
 Lamps can be located in recesses in the walls and 
 ceilings, exposing only the lower half of the lamp 
 
118 HOW TO WIRE BUILDINGS. 
 
 "bulb ; or, they may be concealed entirely and for 
 their cover may have a finely finished piece of 
 artistic glassware, etc. They can also be arranged 
 to form geometrical figures, or placed in the centre 
 of, or at the intersection of the figures forming the 
 decorations. When placed in recesses and covered 
 by glass, the distance between the lamp and glass 
 cover should be such, that the. shape of the carbon 
 or lamp is not visible on or through the glass. 
 
 In lighting theatres, concert rooms, lecture halls 
 and similar places, in which there is some Objective 
 point, such as a stage or platform, the division, 
 location and quantity of. light should be such, that 
 the proper effect at the objective point is secured, 
 and that the light does not strain the eyes of the 
 audience, and that the line of vision is not ob- 
 structed by light between the objective point, and 
 the audience. The lights should be so arranged 
 that there is nb'reflection in the eyes. They should 
 be located at the back of, or considerably above, 
 the "audience. 
 
 When lighting show vrindows in stores, etc., 
 locate the lamps as nearly as possible in the corner 
 where the front intersects with the ceiling, pro- 
 viding a tin shade or reflector having a white 
 surface, and extending the same the entire length 
 of the front, and placing the flat of the lamps 
 
HOW TO WIRE BUILDINGS. 119 
 
 parallel with the reflector, and quite close to it. 
 The sidewalk should be darkened as much as 
 possible to obtain good results. 
 
 To illuminate stained and cathedral glass win- 
 dows or ordinary-sized windows, form a reflector 
 on each side of the window to be lighted, and place 
 therein a sufficient number of lamps, so that a 
 strong light will be obtained, and locate the same 
 at a distance from the windows, so that the 
 diffusion of light will be equal, and that the spots 
 of light, or the carbons of the lamps, will not be 
 discernible. Increase the dimensions of the win- 
 dow, and the number of lamps and distance 
 between same and the window, must be increased. 
 
 84. One of the most difficult problems, in the art 
 of lighting is the illumination of large paintings, 
 etc. In fact, each subject is a separate problem, 
 and must be treated accordingly. The treatment 
 changes according to the size, shape, prevailing 
 colors, if covered with glass or not, and the sur- 
 roundings. The usual method is to place the lamps 
 in a reflector, which is as long as the width of the 
 picture, the reflector is shaped according to the 
 size of the picture and the number of lights and dis- 
 tance between the reflector and picture to be lighted 
 must be such that the light is evenly diffused over 
 the whole surface, and -in such a manner that the 
 
120 HOW TO WIRE BUILDINGS. 
 
 picture can be viewed equally as well from either 
 side, and so that the view will not be impaired by 
 counter-reflection. 
 
 If the painting is suspended from or fastened to 
 the side wall, there should be no side lights located 
 in its near vicinity; and if placed on a stand 
 or easel in the pentre of the floor, care should be 
 taken not to have, any lights at the back of the 
 painting,, which tends to counteract the effeict when 
 Tiewing the picture. 
 
 Paintings placed in a wooden box and covered 
 with gla,ss, are the most difiicult of all, as the sur- 
 rounding objects will be reflected in the glass. To 
 overcome this requires an abundance of light, and 
 the best results can only be .decided by actual ex- 
 periment;. 
 
 It isimpossible to deflnerules governing all con- 
 ditions of lighting. The object of this chapter has 
 been, to describe, iB a .general way, the methods 
 usually employed, and the amount of light neces- 
 sary for general iUuminaition, and to suggest the 
 method usually preferable in. special cases. The 
 style and methods to be employed can only be 
 decided by experience. 
 
HOW TO "WIRE BUILDINGS. 12] 
 
 CHAPTER XIX. 
 
 Distribution of Labor and Hints to Foremen. 
 
 85. The amount of labor is governed by most of 
 the conditions, as stated in previous chapters, but 
 it can be so divided and directed, that the best 
 results will be obtained, from an executive and 
 financial standpoint. 
 
 Let us assume a case in which the plans have 
 been drawn in the drafting-room of the electric 
 lighting company, and -turned over to the foreman 
 in charge, with instructions to install the work. 
 Let us also assume (which is very often the case , 
 that the draftsman had not seen the building. The 
 foreman, from these plans, estimates the amount of 
 material required', and after ordering same, he 
 should familiarize himself with the structure ; ob- 
 serve which portions of the building are in a more 
 advanced state of construction, and the manner in 
 which the labor in the various branches of the 
 building trades, is distributed. 
 
 The plans instruct him as to the general location 
 of wires, and the distribution of current, but he is 
 responsible for the mechanical details, and waste 
 
122 HOW TO WIRE BUILDINGS. 
 
 (if any) of labor. Before the materials are received, 
 he should select a safe place for same, and arrange 
 to keep the " lockup " locked. 
 
 When acquainted with the conditions of the 
 building, he decides upon the number of men, that 
 can be, to good advantage, employed on the work 
 at any one time. The work should be started in 
 that portion of the building, which is in a more 
 advanced state of construction, so tha,t, when once 
 started, it can be completed without interruption 
 or delay. It is advisable to keep the same men in 
 the same part on the different floors of the build 
 ing. So that they will become familiar with the 
 circuits in that section, as nearly all the office, 
 buildings, etc., from the second floor up, are the 
 same. This will enable the man, after completing 
 one floor, to do the work more quickly on each 
 succeeding floor. It also demonstrates whether the 
 amount of work is satisfactory, and when testing 
 the result will show whether the man is careful or 
 not. It is to the foreman's interest to acquaint 
 himself with the capabilities of the men under his 
 supervision, so that he is better enabled to decide 
 which to place on the more exacting and difficult 
 work.. The lengths of the circuits as shown on the 
 plan should be conformed with, as nearly as possi^ 
 ble. The exact sizes of wires as noted on the plan 
 
HOW XO WIRE BUILDINGS. 123 
 
 should be used in all cases, but, should it become 
 necessary to change the work, from the " lay-out" 
 on the plan, the company should be notified in 
 season, so that instructions regarding the change 
 may be given, and that the work will not be 
 delayed, waiting for instructions. 
 
 86. When the top or lamp circuits are nearly 
 completed, provision should be made for testing 
 them. It is also time to arrange for the cutrout 
 boards which are to be set in the panel or. closet. 
 About this time, also, the question of running the 
 mains and feeders should demand attention. 
 
 The foreman should continually stroll through 
 the building, watching the work already completed; 
 the work under way ; observing the advancement 
 in construction of the different portions of the 
 building, and continually calculating as to the 
 method of procedure on his own task, so that the 
 wiring work will not delay the work in other 
 branches, or vice versa. 
 
 One familiar with the method of testing should 
 be appOiilted to do this work, and his duty should 
 not only be to test, but he should locate and repair 
 iaiilts, and "pick up" and finish the innumerable 
 *'odds and ends" which were left undone. One 
 of the most Important labor-saving methods, is to 
 "Ja,y-out" and work all the circuits, which run 
 
/124 HOW TO WIRE BUILDINGS. 
 
 parallel to each otlier, at the same time, all of 
 which, connect to different cut-outs in the same box. 
 It will obviate crosses, and to a great extent sim- 
 plify matters. It is easier to trace the different 
 circuits. 
 
 The same plan is suggested when wires pass 
 through walls, etc., provision can be made, at one 
 time, ior all. The most experienced and careful 
 men should construct the cut-out and switchboards, 
 and run the mains and feeder. 
 
 87. The foreman should provide himself with a 
 note-book, he will find it to be of service both to 
 himself and employer. He should keep a record 
 of, the date, amount,, and kind of miaterial ; the 
 result of each test ; the changes (if any) in the 
 wiring J additions or omissions in the lamps, 
 switches, ^tc, the cause thereof; extra work (if 
 any) and by whose authority ; the general condi- 
 tion of the plant when turned over to the customer; 
 whether dynamo is belted direct to engine ; if so, 
 "whether engine does other work besides driving 
 jflynamo. If belted to pulley countershaftj note 
 variations of speed, if any, and such other, data as 
 jnay be of interest to his employer, and obviate 
 trouble for the future consumer. 
 
HOW TO WIRE BUILDINGS. 125 
 
 CHAPTER XX. 
 
 Preliminary to Rules, Electrical Data, Etc. 
 
 88. + is the sign of addition, and is called plus. 
 Thus 2 + 6 indicates that 6 is to be added to 2 and 
 is read 2 plus 6 or A + B, etc. 
 
 — is the sign of subtraction, and is called minus. 
 Thus 6 — 2 indicates that 2 is to be subtracted from 
 6, and is read, 6 minus 2 or b — a, etc. 
 
 X is the sign of multiplication, and is read, 
 times, or multiplied by. Thus 2x6 indicates that 
 2 is to be multiplied by 6, and is read 6 times 2, 
 and, a X b denotes that multiplication of a x b. 
 
 -H is the sign of division, and is read, divided by. 
 Thus 6 -5- 2 is an indication that 6 is to be divided 
 by 2. 
 
 Division is also indicated by writing the dividend 
 a,bove and the divisor below a short horizontal line 
 
 as in a fraction, thus -^ The exponent of a quan- 
 tity is the number which indicates how often the 
 quantity is used as a factor. Thus, A* indicates 
 that A is to be used as a factor three times, and A' 
 is the same as A x A x A. 
 
126 HOW TO WIRE BUILDINGS. 
 
 A' is read, "A square" or "A second power," 
 A' is read " A cube " or "A third power," and^ if 
 A = 6, A' = 6 X 6 = 36, or A' = 6 X 6 X 6 or 
 6X6 = 36X6 = A = 218. 
 
 The co-efficient is a number written before a 
 quantity" to show how many times the quantity is' 
 to be taken. Thus 3A would show that A is to be 
 taken three times, and if A — 6, 3A = 6 x 3 = 
 3A = 18. 
 
 An algebraic expression, is the expression of a 
 quantity, by means of algebraic symbols ; the 
 symbols indicate the relation of quantities. 
 
 A formula is a method of expi'essing in a simple 
 and concise form, a rule or principle, and show the 
 relation of one to another. Volt is the unit of 
 electrical pressure, (electromotive force) and is 
 represented by E. 
 
 Ampere is that current having an electric pres- 
 sure of 1 volt which flows through a wire having a 
 resistance of one ohm, and is represented by C. 
 
 Ohm is that amount of resistance which, in a 
 conductor, would limit the current, having a pres- 
 sure, of one volt, flowing through same, to one 
 amperejand is represented by R. 
 
 According to Ohm's law, the current in amperes 
 
 is equal to the electromotive force in volts divided 
 
 E 
 by the resistance in ohms, thus, C = w- 
 
HOW TO WIRE BUILDINGS. 127 
 
 The electromotive force in volts is equal to the 
 product of the current in amperes, and the resist- 
 ance in ohms. Thus, E = C x H. The resistance 
 in ohms is equal to the electromotive force in volts 
 
 E 
 divided by the current in amperes. Thus R = -p. 
 
 From these, can be ascertained the current in 
 amperes, when the electromotive force in volts, and 
 the resistance in ohms is known, and, 
 
 The electromotive force in volts, when the current 
 in amperes, and the resistance in ohms is known, 
 and, 
 
 The resistance in ohms, when the current in 
 amperes, and the electromotive force in volts is 
 known. 
 
 Therefore in a machine, the resistance of which 
 
 = .5 ohm and the electromotive force in volts = 
 
 , E = 100 volts 
 100, the current in amperes equals r = 5 c>h.m ~ 
 
 C = 200 amperes, and, C x R = E. 200 amperes 
 
 E = 100 volts _ „ 
 X .5 ohm = 100 volts, and, c= 200 amperes ~ ^ 
 
 = .5 ohm. 
 
 89. To ascertain the available current in ampei'es, 
 not generated at the dynamo, but for consumi^tion 
 by or in the lamps, the resistance of the conductors 
 must be added to the internal resistance of the 
 
128 HOW TO WIRE BUILDINGS. 
 
 dynamo, and if the resistance of the conduc- 
 tors equals .0555 ohm, the available current 
 
 E = 100 volts 100__ _ 
 
 equals, jj ^ g ^^^ ^ R = .0555 ~ .5555 - ^ - 
 
 180 amperes. 
 
 To ascertain the combined resistance of a number 
 of lamps connected in niultiple, divide the resist- 
 ance of one lamp by the number of lamps. Thus, 
 the combined resistance of 40 lamps connected in 
 multiple, the resistance of one equaling 200 ohms, 
 
 200 ohms = R of 1 lamp 
 ^«°1^ ^« 40 lamps = ^ °^"^«- 
 
 To ascertain the combined resistance of a num- 
 ber of lamps connected in series, multiply the 
 resistance of one lamp, .by the number of lamps. 
 Thus, the combined resistance of 10 lamps con- 
 nected in series, the resistance of one lamp equals 
 200 ohms, would be, 
 
 R of 1 lamp X number of lamps: Total resistance 
 200 X . 10 = 2000 ohms. 
 
 To ascertain the combined resistance of a number 
 of series of lamps, the series connected in multiple, 
 divide the resistance of one series by the • number 
 of series. Thus, the combined resistance of 4 series 
 connected in multiple, the resistance of one series. 
 equal 2000 ohms, Avould be, 
 2000 ohms = R of 1 series 
 
 4 series 
 
 = 600 ohms. 
 
HOW TO WIRE BUILDINGS. 129 
 
 Therefore, to ascertain the resistance required in 
 the conductors, so that the loss in same equals, in 
 the desired per cent., a certain proportion of the 
 total resistance, it is necessary, if connected in 
 multiple or series, to first ascertain the combined 
 resistance of the lamps, and assuming, 20 lamps 
 connected in multiple, the resistance of each lamp 
 being 180 ohms, 5 per cent, loss of electrical energy 
 to be allowed, in the conductors ; the distance 
 being 350 feet from the dynamo, therefore, 
 R of one lamp = 180 ohms = g = Total resist of 
 dumber of lamps = 20, alllamps, 
 
 and, 9 ohms representing 95 per cent, of the total 
 resistance of the circuit at 5 per cent, loss, the total 
 
 9 X 100 
 resistance is, — gg — = 9,474 ohms = total resist- 
 ance of lamp circuit. The len^h of the wire 
 being 350 x 2 = 700 feet, and, .474 ohm is the 
 resistance necessary to be contained in a wire 700 
 feet in length, to supply current to 20 lamps located 
 at a distance of 350 feet from the dynamo. If the 
 lamps are connected in series, first ascertain the 
 total resistance of the series, and the method of 
 ascertaining the resistance of the conductor is sim- 
 ilar to that, when the lamps are connected in mul- 
 tiple, assuming the same number of lamps, per cent, 
 of loss and distance from the dynamo, to be the 
 
130 HOW TO WIRE BUILDINGS. 
 
 same as in last example, but, tliat the lamps, will 
 be connected in series instead of multiple, there- 
 fore the combined resistance of all the lamps equals, 
 180 = R of one lamp 
 20 = Number of lamps 
 3600 = Total R of all lamps. 
 5 per cent, being the desired amount of loss in the 
 conductors, therefore 3600 ohms represents 95 per 
 cent, of the total resistance of the lamp circuit, and, 
 
 3600x100 , ,„ ., . . 
 gg = 3789.4 ohms = total K of lamp circuit, 
 
 therefore, 3600 ohms = R of Lamps = 95 per cent, 
 of circuit, and, 189.4 ohms = R of conductors = 5 
 per cent, of circuit resistance. 
 
 90. To ascertain the resistance of a one or a num- 
 ber of corresponding wires, the method is similar 
 to that for lamps. Mil. = .001 of an inch, and 
 when made use of in relation to wiring, is the unit 
 of length, when measuring the diameter, or cross - 
 section of wires. Circular Mil is the unit of area 
 employed in measuring the areas of cross-sections 
 of wire. 
 
 The diameter or cross-section of a wire is 
 expressed in mils, and the area of cross-section in 
 circular mils, therefore a wire, the diameter of 
 which equals i inch = 250 mils, and to ascertain 
 the circular mils it is necessary "to square" the 
 
HOW TO WIRE BUILDINGS. 131 
 
 diameter, d', 250 x 250 = 62500 circular mils. 
 Foot-mil, equals a wire, the length of which 
 equals one foot, and the diameter, one mH ; it is 
 used in practice as a basis for computing the 
 resistance of any given wire, and if the copper is 
 commercially pure (usually 96 per cent, conduc- 
 tivity), the resistance of same, at 75° Fahrenheit, 
 equals 10.79 ohms. 
 
 The resistance of a copper vrire is equal to its 
 length in feet, multiplied by the resistance of one 
 foot-mil, 10.79, and divided by the circular mils, 
 or " the square " of its diameter, therefore, 
 
 L X 10.79 ^ , . *T. 1 *v, * u 
 
 ^ — r"Tf" = ^' ^^^j assuming the length to be 
 
 1500 feet and the circular mils =10.381, the resist- 
 
 , 1500 X 10.79 
 ance would equal -, n 3R1 — 1.559 ohms. 
 
 The cross-section of a copper wire, in circular 
 mils, is found by multiplying the resistance of a 
 foot-mil (10.79) by its length (L) in feet, and divid- 
 ing the result by its resistance (R) in ohms ; there- 
 fore, 
 
 — '—^ = d' or c. m., and, the resistance, and 
 
 length of the wire being the same as in last 
 example, the cross-section in circular mils would 
 
 , 10.79 X 1500 ,^^^^ 
 *^^^^^ 1569 ~ ^ ^" ™' 
 
132 HOW TO WIEK BUILDINGS. 
 
 91. Having ascertained the resistance of the con- 
 ductors, at the desired percentage of loss, for anj*" 
 given number of lamps, the cross-sections of same 
 can be found, as shown in the previous exami^le. 
 To demonstrate: assuming 35 lamps, the R of one 
 = 90 ohms, located at a distance of IfiO feet from 
 the dynamo, and 5 per cent, being the loss of 
 energy desired in the conductors, 
 
 90 ohms R of lamps , „ 
 
 35 1a^p3 = 2.43 ohms = Total R of 
 
 lamps. 2.43 ohms = 95 per cent, of total resistance 
 of circuit, therefore the total resistance of circuit 
 
 2.43 X 100 
 equals, -^ — gg ^ 2.558 ohms — Total R of cir- 
 cuit, and, 2.43 ohms = Total R of lamps, 
 therefore, . 128 ohms = R of conductors. 
 The distance being 160 feet, the total length of the 
 wire equals 320 feet, and the cross-section in cir- 
 cular mils, of a wire that length and resistance, is,, 
 
 10 79 X 320 
 
 ^-^2F — "^ 26.967 c. m. = No.. 6 B. & S. gauge 
 
 wire. 
 
 92. The term "difference of potential" denotes 
 that portion of the electromotive foyce which exists, 
 at, or betw:een, any two points in a circuit, and 
 equals the electromotive force, (in a dynamo) at 
 the point where the armature "cuts" the lines o£ 
 
HOW TO WIRE BUILDINGS. 
 
 133 
 
 force, minus the amount lost in 
 transmission, due to the resistance 
 of the conductor : To illustrate : In 
 an armature, there is created or 
 generated a certain amount of 
 current at a certain pressure ; the 
 pressure decrease? according to the 
 resistance of the conductors ; there- 
 fore, the electrical pressure at the 
 brushes is less, due to the resistance 
 of the armature coils, than in the 
 armature, and less in the feeders, 
 than at the brushes, etc. 
 
 In the diagram A represents an 
 armature of a dynamo, B represents 
 the commutator or brushes, C rep- 
 resents the feeder, D represents the 
 main, and E represents the terminals 
 at, the lamp. At, or in A is "the 
 electromotive force ; that is, the point 
 at which the electrical pressure is the 
 greatest. The pressure at B is less 
 than that at A, due to the resistance 
 of the armature coils, consequently 
 its potency is less ; that is, there "w 
 is at this point a " difference of 
 potential," which is governed by the 
 
 
 
 M 
 (^ 
 
 ^ 
 
134 HOW TO WIRE BtJILDINOe. 
 
 resistances of the conductors, and' the pressure 
 at B plus the amount lost in the armature coils, 
 equals "the electromotive force." The difference 
 of potential in C the feeder, D the mains, and E at 
 the lamp terminals is governed according to the 
 same conditions. Assuming the electromotive force 
 in "A equals 125 volts, and the loss or drop of 
 electrical pressure in the armature equals 1 per 
 cent., the "potential difference" at the brushes B 
 would equal 1231 volts, and, if the loss in the feeder 
 G equals 5 per cent, of that in B^ the difference of 
 potential in C would equal 117 J volts ; and, if ia 
 the main wire D, the loss is equal to 3 per cent, of 
 the pressure in C, the difference of potential in same 
 would equal 114 volts ; and, if the loss in the lamp 
 wires, is. equal to 2 per cent, of the pressure in D, 
 the difference of potential at the lamp terminala 
 would equal lllf volts. 
 
 93. The term " electromotive force," is generally 
 used to denote the pressure at the highest pressure 
 point ; in all other parts of the circuit, the pressure 
 is noted as the potential difference, or difference of 
 potential. 
 
HOAV TO WIRE BUILDINGS. 13fi» 
 
 CHAPTER XXI. 
 
 HuLES FOR Ascertaining Required Sizes of Wire. 
 
 94. The following rules enable us to determine 
 the size of wire necessary, for any number of lamps, 
 at any distance (see safe-carrying capacity), and at 
 any desired loss, expressed in circular mils : 
 
 Rule 1. Multiply the resistance of one foot-mil 
 by twice the distance, and by the number of lamps, 
 and by 100, minus the per cent, loss, and divide 
 the result by the resistance of one lamp multiplied 
 by the percentage of loss. The loss should be 
 expressed as a whole number. Thus, 
 Rof 1 Ft. -mil >«^ 2 X D X No. of lamps 100 — loss 
 
 R of one lamp % loss 
 
 = C. mils. 
 
 Example : 80 lamps, located at a distance of 140 
 feet, R of Lamp = 200 ohms, to determine the size 
 of wire at 5 per cent, loss : 
 Foot-mil = 10.79 ohms. 
 10.79 X 2 X 140 X 80 100—5 _ 
 200 ^ 5 ~ 
 
 241696 95 22961120 „„„„, . ., ^^ „ 
 "200" ^ T= 1000 = 2^^^^ «^^- ™'l^ = ^«- 6 
 B. & S. G. wire. 
 
136 HOW TO WIRE BtJILDINGS. 
 
 Rule 2. To determine the size of wire, the loss 
 or "drop" expressed in volts, multiply the resist- 
 ance of one foot-mil, by twice the distance, and by 
 the number of amperes, and divide the result by 
 the number of volts to be " lost," thus, 
 R of 1 Ft. -mil X 2 X D X amperes 
 Volts drop. = *^- ™^1«- 
 
 Example : 185 100- volt lamps, located at a dis- 
 tance of 260 feet. 
 
 The resistance of each lamp = 140 ohms. Drop 
 = 3 volts. 
 
 It is necessary to find the amount of current, in 
 
 amperes, required for each lamp, and according to 
 
 E 
 Ohm's law, C =t -5- therefore, the current required 
 
 for, or consumed by each lamp equals. 
 
 Volts 100 5 
 
 5KiT40- = T ^™P^^^' ^^<^' 
 
 5 
 -=- X 185 = 132.14 amperes, and, 
 
 10.79 X 2 X 260 X 132.14 „__„ 
 3 = 247123 c. mils. 
 
 95. Where the conditions of the lamps do not 
 change, that is, where the wiring is installed for 
 connection, and use of the same kind of lamps, 
 continuously, it will be found handy to have "a 
 constant" already calculated for the different losses. 
 
HOW TO "WIKE BUILDINGS. 137 
 
 and it is found by multiplying the resistance of one 
 
 loot-mil, by two, and the result, by 100 minus the 
 
 desired loss^ and divide the result by the resistance 
 
 of one lamp multiplied by the loss. The loss to be 
 
 expressed in whole numbers, thus, 
 
 R of Ft. -mil X 2 100 — loss 
 
 R of lamp X loss = constant, and, 
 
 assuming the R of lamp = 200 ohms and the loss 
 
 = 5 per cent. J the constant Tvould be, 
 
 10.79 X ■ 2 100 — 5 _ 
 
 200 ^ 5 "" 
 
 21.58 95 2050 . . „ ^^ 
 
 QQQ X -^ = -.QQQ = constant 2.05 = and, to 
 
 ascertain the size of wire, expressed in circular mils, 
 lor a given number of lamps, a certain distance, at 
 any desired loss, raultiply the number of lamps, by 
 the distance in feet, and the result, by the constant 
 lor the loss desired ; thus, 
 
 No. lamps X distance x constant = cir, mils. 
 Example : The resistance of lamp, and per cent, 
 loss, as in previous example ; determine the size of 
 wire required, for 175 lamps, at a distance of 135 
 feet. 175 X 135 X 2.05 = cir. mils = 48431 = So 
 3B. &S. G. wire. 
 
 ,96. :,The cross-section of wire should be such, 
 that"it will conduct the current without becoming 
 heated to the point where the temperature is greatly 
 
138 HOW TO "WIRE BUILDINGS. 
 
 in excess of that of the surrounding air. Tlie 
 evidence of this condition can be got by grasping 
 the wire with the bare hand. AH wires become 
 heated when a current of electricity is passed 
 tlirough them ; and by increasing the amount, in 
 amperes, in any given wire, the heat is increased. 
 
 According to the rules for wiring, the result is 
 the same in circular mils, for 100 lights one foot as 
 for one light 100 feet. It is eas'ily understood that 
 this is not correct, therefore care must be taken, in 
 short distances to provide a sufficiently large wire, 
 in diameter, so tha,t same will not become unduly 
 heated. The accompanying table is a safe practical 
 guide, and when figuring wire, should the circular 
 mils, per ampere, be less than mentioned in the 
 table, it is advisable to determine the sizes required 
 allowing per ampere, the number as stated therein, 
 rather than by the rules. Allowance in circular 
 mils per ampere, being the safe carrying capacity. 
 
HOW TO WIEE BUILDINGS. 
 
 SAFE CARRYING CAPACITY. 
 
 139 
 
 (as ordered by the board op fire underwriters.) 
 
 Brown & Sharps. 
 
 Birmingham. 
 
 Edison Standard. 
 
 Gadqib No. Ahpekbs. 
 
 Oauob No. Ahfbrbs. 
 
 Gauob No. Amperes. 
 
 0000 175 
 
 0000 175 
 
 200 175 
 
 000 145 
 
 000 ISO 
 
 180 160 
 
 00 120 
 
 00 130 
 
 140 135 
 
 100 
 
 110 
 
 110 110 
 
 1 95 
 
 1 95 
 
 90 95 
 
 2 70 
 
 2 85 
 
 80 85 
 
 3 60 
 
 3 75 
 
 65 75 
 
 4 50 
 
 4 65 
 
 55 65 
 
 5 45 
 
 5 60 
 
 50 60 
 
 6 35 
 
 6 50 
 
 40 50 
 
 7 30 
 
 7 45 
 
 30. 40 
 
 8 25 
 
 8 35 
 
 25 35 
 
 10 20 
 
 10 30 
 
 20 30 
 
 12 15 
 
 12 20 
 
 12 20 
 
 14 10 
 
 14 15 
 
 8 15 
 
 16 5 
 
 16 10 
 
 5 10 
 
 18 3 
 
 18 5 
 
 3 5 
 
 
 20 3 
 
 2 3 
 
140 HOW TO WIRE BUILDINGS. 
 
 CHAPTEK XXII. 
 
 E N E * «• T — P O W E R . 
 
 97. The energy wMcli is developed in a circuit, 
 when a current of on@ ampere flows through a 
 conductor whose resistance is one ohm, is termed a 
 watt. The watt is the electrical unit of power, 
 
 and equals ^r-g horse-power, or, horse-power = 
 
 33,000 foot-lbs., that is, a horse-power equals that 
 power which will raise 33,000 lbs. a distance of one 
 
 foot, in one minute of time, and H. P. = 44.25 
 
 ' ' 746 
 
 foot-lbs. per minute. The number of watts developed 
 in a circuit is determined by multiplying the am- 
 peres by the volts; 
 
 Amperes X volts, or C x E = watts, or C x R. 
 = watts. 
 
 And if expressed in the terms of the mechanical 
 unit (horse-power) 
 
 C E C' R 
 
 746^ or j^Q = horse-power. 
 
 If expressed in foot-pounds, C X E x 44.25, or. 
 C X R X 44.25 = foot-lbs. 
 
HOW TO "WIRE BUILDINGS. 141 
 
 Example : Determine the electrical energy, ex- 
 pressed in horse-power, developed in a dynamo, 
 connected to 750 16-c. p. lamps, each lamp requiring 
 i ampere of current at a pressure of 100 volts. The 
 loss in the wires equals 5 per cent. 
 750 lamps x ^-ampere = 375 amperes, 
 
 C X E = watts 
 
 and, 375 amperes x 100 volts = watts = 37500 and, 
 watts x 44.25 = foot-lbs. 
 
 37500 X 44.25 = 1658375 - the energy, expressed 
 in foot-lbs. , expended in the lamps, and represents 
 95 per cent, of the total as the remaining 5 per cent, 
 is expended or lost in the conductors, therefore 
 1658375 = 95 per cent, of total energy, and 
 
 87284 = 5 " " • " " 
 
 1745659 = Total energy, expressed in foot-lbs., 
 expended in the lamps and conductors, and foot- 
 pounds, divided by 33000 equals horse-power, there- 
 fore, 1745659 - 33000 = 53 horse-power. 
 
 To find the actual horse-power expended at the 
 pulley of the dynamo, assuming the efficiency of 
 the dynamo to be at 90 per cent., and according to 
 the last example, 1745659 foot-pounds were ex- 
 pended in the lamps and conductors, therefore, the 
 efficiency of the dynamo being 90 per cent., it 
 represents only 90 per cent, of the power expended 
 
142 HOW TO WIRE BUILDINGS, 
 
 at the pulley of dynamo, and as 1745659 — 90 %, 
 and, 193962 = 10 % 
 
 1939621 = Total 
 energy in foot-pounds ; therefore, 1989621 -^ 83000 
 = 58.777 = total amount of energy in horse-power 
 expended at the pulley of the dynamo, and if 
 belted to engine, 10 per cent, being lost in the 
 transmission of power, then 
 
 58.777 h. p. = 90 %, and 
 6.53 h. p. = 10 % loss 
 65.307 h. p. represents the amount of 
 horse-power at the pulley of the engine. 
 
 In the first example it was shown that 87.284 foot 
 pounds were expended in the conductors due to 
 their resistance, which equals, 87284 -^ 33000 = 
 2. 645 or 21 horse-power, and the cost, in dollars and 
 -cents, equals 2i x lbs. of coal per h. p. hour x 
 •cost of lbs. of coal 
 
 = $ and cts. 
 This is but another example, of the importance 
 of carefully considering the question of "loss" in 
 conductors. 
 
HOW TO WIRE BUILDINGS. 143 
 
 CHAPTER XXIII. 
 
 Dynamos and Motors. 
 
 98. In setting, connecting, or running a dynamo, 
 or motor, unless you are f amilip,r with all its parts, 
 method of winding, and connections, it is very 
 important that a blue print or diagram, showing 
 the different parts, and method of connections, etc., 
 be procured. 
 
 99. The machine should be located in a clean, dry 
 place, and where the temperature is not high ; it 
 should be isolated, as much as possible, from 
 other machinery, especially in saw mills, machine 
 shops, etc., where more or less dust, or metal filings 
 are flying, but at the same time it should be access- 
 ible. If the machine is set on an ordinary floor, 
 provision should be made against vibration. The 
 base frame should be treated to a coating of hot 
 parafflne, for closing the pores, and a thick coating 
 of shellac. In putting the machine together, care 
 must be taken to have all the parts clean, and all 
 connections, bearings, etc., must be put together so 
 that the " fit " will be perfect. All parts, especially 
 the ai'mature and magnets, must be handled with 
 
144 HOW TO WIRE BUILDINGS. 
 
 the utmost care, and must not be handled anj more 
 than is necessary. 
 
 100. Before starting, adjust and test the brushes 
 for tension. See that the main connections in the 
 circuit are open ; examine all connections ; provide 
 each cup or automatic lubricator, with sufficiwnt oil, 
 and see that the feed is in proper working order. 
 
 In a shunt- wound machine, when up to speed, 
 the brushes can be dropped on the commutator, and 
 if hand regulator is used, the resistance should be 
 thrown out of the field, until the needle on the 
 indicator is at the point showing the required 
 pressure. The lamp at the head of the dynamo is 
 generally a guide. 
 
 101. It is preferable to run the machine, for an 
 hour or so, at full speed, without any current gen- 
 erated, so that the bearings can be worked smooth, 
 and tested before the machine is put to actual 
 work, aiid in case the bearings become heated, the 
 defect must be remedied. 
 
 When a shunt- wound machine is to be connected 
 in circuit, in multiple with another, it should be 
 brought up to speed, and the field resistance grad- 
 ually thrown out, until the pilot lamp, at the head 
 of the machine, is practically at its full normal 
 candle-power. The machine can then be connected 
 iti the circuit, and by watching the pressure indi- 
 
HOW TO WIBE BUILDINGS. 145 
 
 cator, and throwing out the field resistance, the 
 machine will gradually perform its share of the 
 work. When two or more shunt- wound machines 
 are in multiple, all field and line connections should 
 be traced and examined before starting. 
 
 102. In a compound- wound machine, the magnets 
 are wound similarly to those of the ordinary shunt- 
 wound machines, but have, in addition, extra coils 
 in series, and arranged so that according to the 
 number of lamps in use, each receives a certain 
 amount of the current. A change in the number of 
 lamps, connected in the circuit, will cause an 
 increase of current in one, and a proportionate 
 decrease in the other, so that the pressure is kept 
 at a constant point, the series coils acting as an 
 automatic regulator. 
 
 Any number of machines can be run in multiple, 
 provided the pressure or electromotive force of 
 all corresponds. Should the pressure on one 
 be less than that of the others, it is liable to 
 be run by them as a motor. With dynamos 
 connected in multiple, the pressure of all is equal 
 to that of any one machine, but the current, in 
 amperes, is increased according to the capacity 
 of all, for example : Three machines having a 
 capacity of 100, 50 and 25 amperes, respectively, 
 the pressure of each ectuala 125 volts, the com- 
 
146 HOW TO WIBE BUILDINGS. 
 
 bined output would equal 175 amperes at a 
 pressure of 125 volts. 
 
 103. In stopping tlie machine, if running singly, 
 slow the speed of the engine, which reduces the 
 pressure in the dynamo ; throw the resistance coils 
 in the field circuit, if hand regulator is used ; and 
 just before the engine is stopped, break the line 
 connection, and lift the brushes. 
 
 If the, machine is connected in multiple with 
 another, in order to stop or disconnect it from the 
 circuit, regulate its amount of work so that it will 
 be as small as possible, then break the line connec- 
 tion ; but the field must correspond in strength to 
 that in the other machines, so that it may not be 
 run as a motor. 
 
 This same method applies to machines connected 
 to three-wire circuits, and also to compound-wound 
 machines, when the equalizer is kept closed. 
 
 104. Two dynamos connected to the three-wire 
 system, are practically similar to two dynamos 
 connected in multiple ; the positive of one, and the 
 negative of the other machine, are connected to the 
 middle or neutral wire of the circuit. The other 
 pole of each machine forms the positive and nega- 
 tive pole, respectively. 
 
 In starting the machines, each should be started 
 separately, and not at the same time. When one 
 
HOW TO "WIRE BUILDINGS. 147 
 
 machine is connected and running, the second 
 machine, when up to the required pressure, can be 
 connected in the circuit. The method of stopping, 
 as stated, is the same as if in ordinary multiple. 
 
 105. In connecting machines in series, the positive 
 pole of one connects with the negative pole of the 
 next machine ; the current in amperes remains con- 
 stant, but the pressure in volts increases with every 
 additional machine ; the voltage of the machines 
 need not be the same, but the current capacity of 
 each must correspond with the others. 
 
 In constant current machines, when starting, it 
 is only necessary to examine the connections, and 
 have the circuit completed. The line or circuit 
 should never be broken while running, as the field 
 may "burn out," or if broken at the brushes, an 
 arc will be created, that will burn the commutator. 
 In stopping simply slow the speed, if possible^ 
 until the armature stops revolving. 
 
 If connected to shafting, or arranged so that 
 speed cannot be stopped, then open the field circuit, 
 but under no consideration, must the line be broken. 
 
 The method of starting and stopping is the 
 same for a single series machine, or a number of 
 them. 
 
 106. In setting up motors, the same care and 
 attention must be given to all the parts and bear- 
 
148 HOW TO n^IEE BUILDINGS. 
 
 ing, as to dynamos. A blue print or diagram, 
 showing the method of connecting the motor and 
 the starting or regulating- box, and directions for 
 running same, should be provided. 
 
 In a series-wound motor, which is connected in 
 an "arc light" circuit, the connections are simple. 
 The motor is "cut-in" the circuit in the same 
 manner as an arc lamp, a switch is provided and 
 connected in the line (arc light hand switch), which 
 is used for starting or stopping the motor ; as in a 
 series dynamo, the line must never be broken, or, 
 the brushes must never be raised from the commu- 
 tator. 
 
 Constant potential motors are wound in a manner 
 similar to the ordinary shunt- wound dynamo, and 
 with each motor is provided a starting box, com- 
 posed of a number of coils, and constructed 
 somewhat similar to a resistance box, used for 
 regulating the field of shunt- wo and dynamos. The 
 wire forming one side of the circuit is connected to 
 the post of the cross-bar, on the face-board of the 
 starting box, and the cross-bar through a coil in 
 the box forms the connection between one of the 
 field wires and the line. The cross-bar also forms, 
 through a number of coils, the connection between 
 the line and one of the Ibrush wires. The line 
 should always be provided with a double-pole cut- 
 
HOW TO WIEE BUILDINGS. 149 
 
 out and switch. To start the motor, close the 
 switch in the line, and turn th^ connecting strip or 
 cross-bar on the starting box, until it rests on the 
 first connecting plate on each side. Allow it to 
 rest on these for an instant, so that the fields will 
 be charged. As the armature begins to turn, move 
 the cross-bar from plate to plate, which throws out 
 the resistance, and the motor will then have attained 
 its full speed. The movable bar on the starting 
 box must not be allowed to rest on any of the con- 
 necting plates (with the exception of the first, for 
 only a moment), but must be steadily moved to the 
 last plate. This box is not to be used as a regu- 
 lator, but is only for use when starting or stopping, 
 as the capacity of the wires is not sufficient to carry 
 the current for even a short space of time. 
 
 107. A speed regulator is constructed in a some- 
 what similar manner to the starting box, and the 
 cross-Section of the wires is such, that they can 
 carry the current without unduly heating. In 
 stopping, turn the handle, at the starting box, in 
 the opposite direction to that when starting, and 
 when it is brought to the last connection, the circuit 
 is broken, although it is more preferable to allow 
 the bar to rest on the connecting plate, next to the 
 last, and break the connection at the line switch. 
 
150 HOW TO -WIEE BUILDINGS. 
 
 CHAPTER XXIV. 
 
 Pullets. 
 
 108. In all machines, whether a dynamo or motor, 
 the pulley is furnished with -the machine. The 
 width ol face and diameter, have been determined 
 by the maker. The size of the pulley on the 
 dynamo has been determined, according to the 
 speed and power required to drive it when at its 
 full rated capacity. The pulley on the motor is 
 determined by the rated speed at which the motor 
 is to run, and its rated horse-power. 
 
 The pulleys on the machines should not be altered, 
 or pulleys of other dimensions used ; and where 
 conditions exist, which necessitate a change in size,, 
 the maker should be notified. He will either make 
 the change, or forward instructions regarding the 
 matter. 
 
 In dynamos driven by an engine, the dimensions 
 of the driving wheel is usually determined by the 
 electric lighting company or the maker of the 
 engine. The diameter is determined by the number 
 of revolutions per minute of the engine shaft, the 
 revolutions, per minute, necessary for the capacity 
 
HOW TO "WIRE BUILDINGS. 151 
 
 of the dynamo, and the diameter of the dynamo 
 pulley. When the dynamo is belted to a pulley on 
 a countershaft, the shaft must be considered as the 
 shaft on the engine. 
 
 The face or width of a pulley is a trifle larger 
 than the width of the belt. 
 
 109. To ascertain the required diameter of the 
 ■driving pulley: Multiply the diameter of the 
 dynamo pulley by the number of revolutions per 
 minute required, and divide the product, by the 
 number of revolutions per minute, of the shaft, 
 Dia. of Dynamo Pulley x required speed _ 
 Revolutions of shaft, per minute, ~ 
 diameter of driving pulley. 
 
 Example : To determine the diameter of pulley 
 to drive a dynamo, having a pulley 10 inches in 
 diameter, and requiring 1,500 revolutions per 
 minute. The revolutions of the shaft per minute 
 = 225, therefore, 
 
 — 02^ = 66f inches = diameter of driving 
 
 pulley. 
 
 In motors, the dimensions of the pulley being 
 already determined by the maker, the speed at 
 which the machinery or shaft is driven by the 
 motor, depends on the speed of the motor, and the 
 diameter of the pulleys. The diameter of the 
 
152 HOW TO WTEE BUILDINGS. 
 
 pulley on the machine or shaft to be driven at a 
 certain speed, depends upon the speed and diameter 
 of the motor pulley. 
 
 To ascertain the diameter of the driven pulley for 
 any desired speed or number of revolutions per 
 minute, multiply the revolutions per minute, of the 
 motor pulley, by its diameter, and divide the 
 product, by the number of revolutions, desired for 
 the driven pulley. Thus, 
 Speed of motor X diameter of motor pulley 
 Desired number of revolutions for driven pulley ~ 
 Diameter, in inches, of driven, pulley. 
 
 Example : To determine the diameter of a pulley 
 requiring 200 revolutions per minute, the rated 
 speed of the motor being 1,200 revolutions per 
 minute, and the diameter of pulley on same equals 
 9 inches, therefore, 
 
 200 — = 54 inches = diameter of driveu 
 
 pulley. 
 
 By these methods, the driving or driven pulley 
 can be ascertained. 
 
HOW TO WIRE BUILDINGS. 153 
 
 CHAPTER XXV. 
 
 Belting. 
 
 110. All belts and lacing should be the best pro- 
 curable. The belt should be placed on the pulley, 
 with the smooth side in contact. If the belt tends 
 to run to either edge of the pulley, move the 
 dynamo or motor in that direction, until the belt 
 remains in the centre. 
 
 Do not skimp on the width or length of the belt, 
 it being desirable to have it a trifle larger than ia 
 actually necessary rather than too small. 
 
 In dynamos or motors, the width of the belt ia 
 governed by the width of the face of the pulley on 
 same. The pulley is . usually one inch wider than 
 the belt. 
 
 Belts driven horizontally give better satisfaction 
 than those driven in a vertical position, as the arc 
 of contact is increased in horizontal driving. 
 
 111. Avoid excessive strain, and protect the belts 
 from dirt, exposure, extreme dampness or extreme 
 dryness. Applying neats-foot oil occasionally will 
 keep the belt soft and pliable. 
 
154 HOW TO WIRE BUILDINGS. 
 
 112. A single belt traveling 1,000 feet per minute, 
 transmits one horse-power, provided the arc of 
 contact equals 180°, or if it binds or touches one- 
 half the surface of the circumference of the pulley. 
 
 Rule for ascertaining the width of belt for any 
 desired horse-power : 
 Width of belt x speed of belt in ft. x arc of contact 
 
 1000. 
 = h. p. 
 
HOW TO WIBE BtTILDINGS. 155 
 
 CHAPTER XXVI. 
 
 Engines. 
 
 113. Although wiremen are not expected to be 
 steam engineers, yet there are times when a knowl- 
 edge of starting and stopping an engine may be 
 very serviceable, as in the case of sudden sickness 
 of the engineer in charge of plant, and where illum- 
 ination is imperatively required. 
 
 The engines mostly used for drixdng dynamos are 
 of "the horizontal, high-speed type. The steam 
 pressure is usually 80 pounds to V the square inch, 
 to obtain the required speed of revolution. 
 
 114. Before starting an engine, supply all the oil 
 cups and ' ' self ' ' -lubricators with a sufficient amount 
 of oil, and see that the ' ' feed ' ' is properly adjusted . 
 Open the rear ports, or drips, usually located in 
 the back of and under the cylinder, to allow any 
 condensed water to run out. Set the engine on its 
 "centre" and then slightly open the steam valve, 
 to heat the piston and cylinder. When one side is 
 " warmed up " turn the pulley over to the opposite 
 " centre" and heat the opposite part of the cylin- 
 der, piston, etc. When the engine is heated, and 
 
166 HOW TO WIRE BUILDINGS. 
 
 the steam gauge indicates the pressure required, 
 open fully the exhaust valve, close the rear ports, 
 or drip cocks, and slightly open the steam valve. 
 Turn the driving pulley in the proper direction, 
 and when the engine is running slowly, note whether 
 it is running smoothly. Keep opening the steam 
 valve gradually, until it is fully opened, and the 
 engine is running at full speed. Attention can then 
 be given to the starting of the dynamo. 
 
 115. While the engine is running, observe from 
 time to time the amount of pressure indicated at 
 the gauge, and watch the lubricators, etc. 
 
 If any loud noise or pounding be heard in the 
 engine, shut down at once, as water may from some 
 reason have been carried into the cylinder, and if 
 the engine were kept running, the result would be 
 that the cylinder-head would be blown out, and the 
 engine be ruined. 
 
 To stop the engine, gradually close the steam 
 valve, be careful that the engine is not stopped too 
 sudden. Slowly bring the driving wheel to a stand- 
 still. "When the engine is stopped, close the feed 
 of the lubricators, clean all parts of the engine, and 
 cover it with the cloth provided for the purpose. 
 
 116. Under no consideration must it be attempted 
 to repair any part or parts of the engine, and it is 
 
HOW TO WIRE BUILDINGS. 157 
 
 suggested that, unless the engine is in good order, 
 and the case urgent, the wireman should not in any 
 manner handle the engine, unless tie is an expe- 
 rienced engineer. 
 
158 HOW TO WIRE BUILDINGS. 
 
 CHAPTER XXVII. 
 
 Conclusion. 
 
 117. Wiremen should familiarize themselves with 
 the different kinds and qualities of material, so that 
 they may be enabled to get the best of any partic- 
 ular kind. In the matter of appliances, they should 
 know just what is the best for the special purpose. 
 New appliances, etc., are being placed 'on the 
 market continually, and unless a knowledge of the 
 same is acquired, antiquated, obsolete and' inferior 
 materials and devices will be used to the disad- 
 vantage of the customer. The writer would advise 
 all wiremen to subscribe to some journal devoted 
 exclusively to the discussion and publication of 
 electrical engineering work. Hardly a week goes 
 bj- but what some one or more articles treat on new 
 metliods of wiring and kindred work. It is very 
 instructive and at the same time interesting. We 
 are also enabled, through the same source to obtain 
 information .on the various appliances, and where 
 the same can be purchased. We are better able to 
 keep in line with all improvements in all; branches ; 
 as an instructor, the press has no equal, and it has 
 
HOW TO WIRE BUILDINGS. 159 
 
 . the advantage, moreover, of continually devising 
 new ways by whicli the wireman may get greater 
 profit from his experience and rise to larger 
 responsibilities and opportunities. 
 
160 
 
 HOW TO WIRE BUILDINGS. 
 
 Tables op Different Gauges, with their Respective. 
 Diameters and Areas. 
 
 Browns & Sharpe. 
 
 BiRMINQHAM. 
 
 No. of 
 
 Diameter 
 
 Area in 
 
 No. Of 
 
 Diameter 
 
 Alva in 
 
 Gauge. 
 
 in Mils. 
 
 C M = d2. 
 
 Gauge. 
 
 in Mils. 
 
 c iu = d». 
 
 4-0 
 
 .4600 
 
 211600 
 
 4-0 
 
 .454 
 
 206116 
 
 
 
 
 3-0 
 
 .425 
 
 180625 
 
 3-0 
 
 .4096 
 
 167805 
 
 
 
 
 2-0 
 
 .3648 
 
 133079 
 
 2-0 
 
 .380 
 
 144400 
 
 
 
 
 
 
 .340 
 
 115600 
 
 
 
 .3249 
 
 105592 
 
 
 
 
 
 
 
 1 
 
 .300 
 
 90000 
 
 1 
 
 .2893 
 
 83694 
 
 2 
 
 ,284 
 
 80656 
 
 2 
 
 .2576 
 
 66373 
 
 3 
 
 .259 
 
 67081 
 
 3 
 
 .^294 
 
 52634 
 
 4 
 
 ,238 
 
 56644 
 
 
 
 
 5 
 
 .220 
 
 48400 
 
 4 
 
 .2043 
 
 41742 
 
 6 
 
 .203 
 
 41209 
 
 5 
 
 .1819 
 
 33102 
 
 7 
 
 .180 
 
 32400 
 
 6 
 
 .162 
 
 26244 
 
 8 
 
 .165 
 
 57225 . 
 
 1 
 
 .1443 
 
 20822 
 
 9 
 
 .148 
 
 21904 
 
 8 
 
 .1285 
 
 16512 
 
 10 
 
 .134 
 
 17956 
 
 9 
 
 ,1184 
 
 13110 
 
 11 
 
 .120 
 
 14400 
 
 10 
 
 .1019 
 
 10381 
 
 12 
 
 .109 
 
 11881 
 
 11 
 
 .0907 
 
 8226 
 
 13 
 
 .095 
 
 9025 
 
 12 
 
 .0808 
 
 6528 
 
 14 
 
 .083 
 
 6889 
 
 13 
 
 .072. 
 
 5184 
 
 15 
 
 .072 
 
 5184 
 
 14 
 
 .0641 
 
 4110 
 
 16 
 
 .065 
 
 4225 
 
 15 
 
 .0571 
 
 3260 
 
 17 
 
 ,058 
 
 3364 
 
 16 
 
 .0508 
 
 2581 
 
 18 
 
 ,049 
 
 2401 
 
 17 
 
 .0452 
 
 2044 
 
 19 
 
 .042 
 
 1764 
 
 18 
 
 .0403 
 
 1624 
 
 
 
 
 19 
 
 .0359 
 
 1253 
 
 20 
 
 ,035 
 
 1225 
 
 20 
 
 .032 
 
 1024 
 
 21 
 
 ,032 
 
 1024 
 
 21 
 
 .0285 
 
 820 
 
 22 
 
 .028 
 
 784 
 
 22 
 
 .0253 
 
 626 
 
 23 
 
 ,025 
 
 625 
 
 23 
 
 .0226 
 
 510 
 
 24 
 
 ,022 
 
 484 
 
 24 
 
 .0201 
 
 404 
 
 25 
 
 ,020 
 
 400 
 
 25 
 
 .0179 
 
 320 
 
 26 
 
 ,018 
 
 324 
 
BOW TO WIRE BUILDINGS. 
 
 161 
 
 WEIGHT OF COPPER WIRE. 
 
 No. 
 
 1 OsB Thousand Feet. 
 
 Onb Milk. 
 
 1 B. & S. 
 
 B. W. G. 
 
 B. &S. 
 
 B. W. G. 
 
 - 0000 
 
 039.33 
 
 - 622.36 
 
 3375 
 
 3286 
 
 000 
 
 507.01 
 
 540.22 
 
 2677 
 
 2884 
 
 00 
 
 ■402.09 
 
 436.56 
 
 2123 
 
 2305 
 
 
 
 319.04 
 
 349.63 
 
 1684 
 
 1846 
 
 1 
 
 252.88 
 
 272.17 
 
 1335 
 
 1437 
 
 2 
 
 200.64 
 
 243.76 
 
 1058 
 
 1287 
 
 3 
 
 159.03 
 
 202.84 
 
 839 
 
 1071 
 
 •4 
 
 126.12 
 
 171.21 
 
 665 
 
 904 
 
 5 
 
 100.01 
 
 146.40 
 
 528 
 
 773 
 
 6 
 
 79.32 
 
 124.43 
 
 418 
 
 657 
 
 i 
 
 62.90 
 
 97.92 
 
 332 
 
 547 
 
 8 
 
 49.88 
 
 82.39 
 
 263 
 
 435 
 
 9 
 
 39.56 
 
 66.29 
 
 209 
 
 350 
 
 10 
 
 31.37 
 
 54.36 
 
 166 
 
 287 
 
 11 
 
 24.88 
 
 43.56 
 
 131 
 
 230 
 
 12 
 
 19.73 
 
 35.98 
 
 104 
 
 190 
 
 13 
 
 15.65 
 
 27.27 
 
 83 
 
 144 
 
 14 
 
 12.41 
 
 20.83 
 
 65 
 
 110 
 
 15 
 
 9.84 
 
 15.72 
 
 52 
 
 83 
 
 16 
 
 7.81 
 
 12.88 
 
 41 
 
 68 
 
 17 
 
 6.19 
 
 10.18 
 
 33 
 
 53i 
 
 18 
 
 4.92 
 
 7.20 
 
 26 
 
 38 
 
 19 
 
 3.93 
 
 5.30 
 
 20i 
 
 28 
 
 20 
 
 3.09 
 
 3.60 
 
 16i 
 
 19i 
 
 21 
 
 2.45 
 
 3.09 
 
 13 
 
 16i 
 
 22 
 
 1.94 
 
 2.37 
 
 lOi 
 
 m 
 
 23 
 
 1.54 
 
 1.94 
 
 H 
 
 lOi 
 
 24 
 
 1.22 
 
 1.47 
 
 H 
 
 7i 
 
 25 
 
 .97 
 
 1.22 
 
 H 
 
 6^ 
 
 26 
 
 .77 
 
 .95 
 
 4 
 
 5 
 
 27 
 
 .61 
 
 .75 
 
 3i 
 
 4 
 
 28 
 
 .48 
 
 .6li 
 
 H 
 
 H 
 
 29 
 
 .38 
 
 .50 
 
 2 
 
 2| 
 
 30 
 
 .30 
 
 .42 
 
 If 
 
 H 
 
162 HOW TO WIRE BUILDINGS. 
 
 Table Showing Fbactiomb ov an Inch Reduced to 
 Decimal Equivalents. 
 
 j>j .eqtials .015625 
 
 -jlj " ,031250 
 
 -^ " .046875 
 
 VV " .062^00 
 
 ^ " .078125 
 
 -^ " .093750 
 
 ^ " .109375 
 
 I ■' .125000 
 
 ,V " .140625 
 
 ....•/^.... " .156250 
 
 ^ . " .171875 
 
 .^ . " .187500 
 
 fl-. ■. " .203125 
 
 ....-^ '' .218750 
 
 ^i- -. " .234375 
 
 i " .250000 
 
 a " .265625 
 
 ....■^ '. " .281250 
 
 fl " .296875 
 
 -^-^ " .312500 
 
 fj- " .328125 
 
 ^ ...i " .343750 
 
 H ...• " .359375 
 
 I " .375000 
 
 ff " .390625 
 
 ...-H--. " .406250 
 
 fj " .421875 
 
 .......... r^ , " .437500 
 
 U • " .453125 
 
 H , " .468750 
 
 U " .484375 
 
 i " .500000 
 
DIMENSIONS, WEIGHT AND RESISTANCE 
 
 
 
 
 
 Wbiobt. 
 
 Oavob 
 
 No. 
 
 Diameter In 
 Mils, 
 
 Sect, area in 
 Circular Mils. 
 
 ■ 
 
 
 
 Lbs. per Foot. 
 
 Lbs. per Ohm. 
 
 0000 
 
 .46 
 
 211600. 
 
 .640525 
 
 13139.29 
 
 000 
 
 .40964 
 
 167805. 
 
 .507955 
 
 8356.95 
 
 00 
 
 .8648 
 
 133079. 
 
 .40384 
 
 6193.13 
 
 
 
 .82486 
 
 103584. 
 
 :319457 
 
 826J.84 
 
 1 
 
 .2898 
 
 83694. 
 
 .253348 
 
 3054.015 
 
 z 
 
 .25763 
 
 66378. 
 
 .200915 
 
 1391. 80> 
 
 3 
 
 .23943 
 
 52634. 
 
 .159825 
 
 813.709 
 
 4 
 
 .20431 
 
 41743. 
 
 .126357 
 
 522.839 
 
 5 
 
 .18194 
 
 88103. 
 
 .10038 
 
 831.809 
 
 6 
 
 .16308 
 
 26251. 
 
 .0794616 
 
 303.062 
 
 7 
 
 .14428 
 
 20817. 
 
 .0630134 
 
 137.07 
 79.9J58 
 
 8 
 
 .13849 
 
 16510. 
 
 .0499757 
 
 
 
 .11443 
 
 13094. 
 
 .039637 
 
 50.3886 
 
 10 
 
 .10189 
 
 10382. 
 
 .0314356 
 
 81.6036 
 
 11 
 
 .090743 
 
 8234. 
 
 .034935 
 
 19.883 
 
 12 
 
 .080808 
 
 6530. 
 
 .0197665 
 
 13.5034 
 
 18 
 
 .071961 
 
 5178. 
 
 .0156753 
 
 7.86S19 
 
 14 
 
 .064084 
 
 4107. 
 
 .0134314 
 
 4.51088 
 
 15 
 
 i057()C8 
 
 8257. 
 
 .0098.i84 
 
 3.11015 
 
 16 
 
 .05(183 
 
 2583. 
 
 .0078179 
 
 1.95501 
 
 17 
 
 .045357 
 
 2048. 
 
 .0063 
 
 1.33013 
 
 18 
 
 .040303 
 
 1634. 
 
 .004917 
 
 " .773677 
 
 19 
 
 .03589 
 
 1288. 
 
 .0038991 
 
 .486534 
 
 20 
 
 .031961 
 
 1021. 
 
 .00:J0932 
 
 .805979 
 
 21 
 
 .028463 
 
 810. 
 
 .0024522 
 
 .193439 
 
 33 
 
 .035347 
 
 043. 
 
 .0019448 
 
 .121037 
 
 23 
 
 .023571 
 
 509. 
 
 .0015421 
 
 .076105 
 
 24 
 
 .0201 
 
 404.1 
 
 .001223 
 
 .0478624 
 
 25 
 
 .0179 
 
 320. 
 
 .0009699 
 
 .0301033 
 
 26 
 
 .01594 
 
 354. 
 
 .0007691 
 
 .0168719 
 
 37 
 
 .014195 
 
 201. 
 
 .0006099 
 
 .0119056 
 .0074748 
 
 28 
 
 .012641 
 
 159.8 
 
 .0004887 
 
 29 
 
 .011357 
 
 126.7 
 
 .0003836 
 
 .0047087 
 
 80 
 
 .010025 
 
 100.5 
 
 .0003043 
 
 .00396174 
 
 81 
 
 .008928 
 
 79.7 
 
 .0003413 
 
 .0018306 
 
 32 
 
 .00795 
 
 63. 
 
 S.0001913 
 
 .00117133 
 
 83 
 
 .00708 
 
 50.1 
 
 .0001517 
 
 .000733789 
 
 84 
 
 .008804 
 
 89.74 
 
 .0001203 
 
 .0004631 
 
 35 
 
 .005614 
 
 81.5 
 
 .0000954 
 
 .000291373 
 
 86 
 
 .005 
 
 25. 
 
 .00007563 
 
 .000183369 
 
 37 
 
 .004453 
 
 19.8 
 
 .00006003 
 
 .000115298 
 
 88 
 
 .003985 
 
 15.72 
 
 .00004759 
 
 .00007^741 
 
 39 
 
 .002531 
 
 13.47 
 
 .00003774 
 
 .0000455828 
 
 40 
 
 1 
 
 .003144 
 
 9.88 
 
 .00002993 
 
 .0000369803 
 
OF BARE COPPER WIRE— AM, GAUGE. 
 
 JJESOTB 
 
 -Feet. 
 
 Rksistauce— Ohms. | 
 
 Oauoe 
 
 No. 
 
 Per Lb. 
 
 Per Ohm. 
 
 Per Foot. 
 
 Per Lb. 
 
 • 1.56123 
 
 20497.7 
 
 .000048786 
 
 .0000761656 
 
 0000 
 
 1.9687 
 
 16255.27 
 
 .000061519- 
 
 .00018111 
 
 000 
 
 S.4824 
 
 ■12891.37 
 
 .0000775713 
 
 .006193563 
 
 00 
 
 8.1S03 
 
 10233.08 
 
 .000097818 
 
 .0003063 
 
 
 
 3 91714 
 
 8107.49 . 
 
 .000123343 
 
 .00047686d 
 
 1 
 
 4.97723 
 
 6439.58 
 
 .00015553 
 
 ,000774113 
 
 8 
 
 6.8765 
 
 6098.61 
 
 .000196133 
 
 .00123103 
 
 3 
 
 7.9141 
 
 4048.6 
 
 .000347304 
 
 ,00191363 
 
 4 
 
 9 97983 
 
 8306.61 
 
 .000311856 
 
 .00311237 
 
 5 
 
 12.5847 
 
 2543.89 
 
 .000393355 
 
 .00494898 
 
 6 
 
 15.8696 
 
 2015.51 
 
 .000495903 
 
 ,0078)166 
 
 7 
 
 80.0097 
 
 1599.8 
 
 .000635376 
 
 ,0135116 
 
 8 
 
 25.339 
 
 1268,44 
 
 .00078837 
 
 .0198853 
 
 9 
 
 31.8313 
 
 1055.66 
 
 .00099437 
 
 .031648 
 
 10 
 
 40.1302 
 
 797.649 
 
 .0012537 
 
 ,0502987 
 
 n 
 
 60.5906 
 
 083.655 
 
 .0015809 
 
 ,0799783 
 
 12 
 
 63.7948 
 
 601.68 
 
 .0019935 
 
 .127172 
 
 13 
 
 80.4415 
 
 897.833 
 
 .0025137 
 
 ,831713 
 
 14 
 
 101.4865 
 
 815.483 
 
 .00316975 
 
 .321539 
 
 15 
 
 127.12 
 
 250.184 
 
 .00399707 
 
 .611504 
 
 16 
 
 161.29 
 
 198.409 
 
 .0060401 
 
 .813918 
 
 17 
 
 203.374 
 
 157.85 
 
 .0063553 
 
 1.29253 
 
 18 
 
 856.463 
 
 184.777 
 
 .00801436 
 
 8.0554 
 
 19 
 
 333 399 
 
 98.9338 
 
 .0101058 
 
 3.2683 
 
 20 
 
 407.815 
 
 78.478 
 
 .0127433 
 
 6.19871 
 
 21 
 
 6f4.193 
 
 63.836 
 
 .0160678 
 
 8.26197 
 
 83 
 
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