The Burling Vocational Series B. B. Burling, Editor. LEAF SHOP MANUAL r and POWER WIRING BY BEVERLY B. BURLING, S.B. E.E, AND JAMES H. LAUERMAN One of a Series of Manuals Covering Trade Subjects. Compiled Especially for Technical High, Continuation, and Trade Schools. Property of The Bruce Publishing Co. Milwaukee, Wis. EL The Burling Vocational Series B. B. Burling, Editor. LOOSE LEAF SHOP MANUAL LIGHT and POWER WIRING A Manual for Technical High Schools, Trade Schools and Evening Classes in Applied Electricity BY BEVERLY B. BURLING, S.B. E.E., Industrial Training for Men and Boys, Milwaukee Board of Education; Extension Department, University of Wisconsin; Past Supervisor of Co-operative Education. AND JAMES H. LAUERMAN Instructor (Electrical Trade Work), Boys’ Technical High School of Milwaukee, Wis. A The Bruce Publishing Co., Milwaukee. Wis. V Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring TABLE OF CONTENTS Title Table of Contents Electric Symbols General Instructions Job L- 1 — Wire Splicing. L- 2 — Soldering with Iron. L- 3 — Soldering with Torch. L- 4 — Taping of Splices. Open Wiring L- 5 — Rules, Methods, Dead Ending, Use of S 1 Switches. L- 6 — Rules, Use of D. P. S. T. Knife Switches. L- 7 — Use of S 2 Switches. L- 8 — Series Circuit. L- 9, 10 — Parallel Circuits. L-ll — Two Point Control, Use of S 3 Switches. L-12 — Entrance Switch and Cut-out, Open Loop. L-13 — Two Point Control, Use of S. P. D. T. Knife Switches. L-14 — Three Point Control, Use of S 3 and S* Switches. L-15 — Closed Loop System of Wiring. L-16 — Use of D. P. D. T. Switch in place of S* Switch. L-17 — Use of D. P. D. T. Knife Switches. L-18 — Four Point Control System. L-19, 20 — Use of Knife Switches on Three Point Control Systems. L-21 — Use of S 4 Switches in place of S 3 Switches. L-22 — Control of Upper and Lower Hall Lights. L-23 — Use of Combination Knife and Snap Switches, S 3 , D. P. D. T., S 4 , S. P. D. T. L-24 — Two Point Control of Three Wire System. L-25 — Use of Electrolier Snap Switches. L-26 — Use of S 1 and S 3 Switches in Combination. L-27 — Carter System or Live Line 3 Way. L-28 — Use of S* as a Master Switch. L-29 — Control of Two Circuits Individually or Simultaneously. Use of S l and S 3 Switches. L-30 — Use of a Master Switch on an S’ System. L-31 — Use of a Master Switch to Control all the Lights in a House. L-32 — Street Car Lighting System. Series System with Transfer Switch. Concealed Knob and Tube Wiring, Rules, etc. L-33 — One Ceiling and One Bracket Light, Rules, Methods. L-34 — Ceiling Light Controlled from Two Points, Base Plug, Rules. L-35 — Ceiling, Two Bracket and Base Receptacle Outlets, Use of S\ S’ and S 4 Switches. Wood Molding, Rules, etc. L-36 — Construction of a Mitre Box, Mitering. L-37 — Wire for One Ceiling, One Bracket and One Base Receptacle. L-38 — Use of Two and Three-Wire Molding, Two Ceiling, Two Brackets and Base Recep- tacle. Metal Moldings, Rules, Etc. L-39 — Cutting, Mitering and Bending. L-40 — Use of Metal Molding Fittings. Wire for One Ceiling, One Base Receptacle and Three Bracket Outlets. L-41 — Ceiling Circuits Controlled by Pull Chain Switches. L-42 — Complete Metal Molding System including, Ceiling, Bracket and Base Outlets. Methods of Supporting. Rigid Conduit, Rules, Methods of Bending L-43 — Cutting, Reaming, Threading and Bending }4-in. and 34-in. Pipe. L-43-a — Conduit Bending 90 degree Bends. L-43-b — Conduit Bending, Offset, Gooseneck, Compound Quarter Bend. L-44 — Wiring Plan, Routing Plan for Ceiling and Bracket Outlets, Concealed Wiring, Rules, Fittings. L-45 — Concealed System. Use of S 2 Flush Switches. Wire for Ceiling and Bracket Outlets. L-46 — Exposed Conduit System. Use of S 3 Snap Switches, Fittings. Wire for Ceiling, Bracket and Base Receptacle Outlets. L-47 — Concealed System. A Border Lighting Sys- tem on Two Circuits. Rules. L-48 — Concealed System, Flush Switches. Wire for Ceiling and Bracket Outlets. Bracket Lights to be Controlled by an Electro- lier Switch. Rules. Flexible Steel Conduit, Connectors, Couplings, Fittings, Rules L-49 — Use of Snap Switches. Wire for Two Ceil- ing and One Bracket Outlet. L-50 — Use of S 3 Flush Switches. Wire for One Ceiling, One Bracket and One Base Re- ceptacle Outlet. L-51 — Wire for S 1 and S 2 Flush Switches to Con- trol Ceiling and Bracket Lights. L-52 — Wire for Three Ceiling Outlets Controlled by an Electrolier Snap Switch also Bracket and Base Receptacle Outlets. Flexible Steel Armored Cable, Rules, Fittings, Boxes, Methods L-53 — Wire for Ceiling, Bracket and Base Outlets Using Flush Switches, Rules. L-54 — Wire for Two Ceiling, One Bracket and Base Outlets Using S 1 and S 3 Switches, Rules. L-55 — Wire for Ceiling, Bracket and Base Outlets Using S 3 and S 4 Switches. L-56 — Wire for Four Ceiling, Two Bracket and One Base Outlet. Fixtures, Wiring and Construction Service, Meters and Meter Loops, Rules, Methods, etc. L-57 — Use of Terminal Fittings, Wire for Four Family Apartment. L-58 — Use of Multiplex Boxes, Wire for Two- Wire Service, 2-Wire Meter. L-59 — Use of Multiplex Boxes, Wire for Three- Wire Service, Two 2-Wire Meters. L-60 — Use of Multiplex Boxes. Wire for Three- Wire Service, Using One 3-Wire Meter. L-61 — Use of Multiplex Boxes. Wire for Three- Wire Service. One 2-Wire and One 3-Wire Meter. L-62 — Use of Multiplex Boxes. Wire for Three- Wire Service Using, Two 3-Wire Meters. L-63 — Use of Multiplex Boxes. Wire for Three- Wire Service. Using One 3-Wire D. C. Meter. L-64 — Use of Demand Meter. Wire for Three- Wire Service Using Two Wright De- mand Meters and One 3-Wire Meter. L-6S — Use of Multiplex Boxes. Wire for Three Customers Using Two 2-Wire and One 3-Wire Meter. L-66 — Use of Compensator Type Square D. Switch Wire for Three-Wire Service and 2- Wire Meter. L-67 — Use of Multiplex Boxes. Wire for Three- Phase Service and One 3-Phase Meter. Typical Installations for Large Apartment Buildings 1 — Use of Two and Three-Wire Meters with Customer’s Cabinet in the Basement. 2 — Use of Two and Three-Wire Meters with Customer’s Distribution Cabinets located in respective Apartments. Motor Installations, Rules, Methods, etc. L-68 — D. C. Compound Motor Wired up with Switch and Starting Box. L-69 — A. C. Three-Phase Motor Using Safety Starting Switch. Typical Floor Plan of Residence Cellar, First and Second Floor. Resuscitation from Electric Shock Useful Data Copyright 1922. B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring 4 5.I.M STANDARD SYMBOLS FOR WIRING PLANS As recommended and adopted by the Association of Electragists, International, The American Institute of Archi- tects and the American Institute of Electrical Engineers, and approved by the American Engineering Standards Com- mittee on March 6, 1924. P- r o ® o#o © K> & .« i© i©2 ® 0 0 I© a a s 5 Ceiling outlet. Ceiling outlet (gas and electric). Ceiling lamp receptacle. Specifications to de- scribe type such as key, keyless or pull chain. Ceiling outlet for extensions. Ceiling fan outlet. Pull Switch. Drop cord. Wall bracket. Wall bracket (gas and electric). Wall outlet for extensions. Wall fan outlet. Wall lamp receptacle. Specifications to describe type such as key, keyless or pull chain. Single convenience outlet. Double convenience outlet. Junction box. Special purpose outlet. Lighting, heating and power as described in specifications. Special purpose outlet. Lighting, heating and power as described in specifications. Special purpose outlet. Lighting, heating and power as described in specifications. Exit light. Floor outlet. Floor elbow. Floor tee. Local switch — single pole. Local switch — double pole. Local switch — 3 way. Local switch 4 way. S D Automatic door switch. s' 1 Key push button switch. s l Electrolier switch. s p Push button switch and pilot. s" Remote control push button switch. ED Tank switch. o' 1 © Motor. % fMC] Motor Controller. Lighting panel. 0 s: vm Power panel. flD a Heating panel. Pull box. 5- a: Cable supporting box. an a Meter. tr Transformer. > Branch circuit, run concealed under floor above. 0" Branch circuit, run exposed. 5 — Branch circuit, run concealed under floor. II lit II II III II II II II III llll II II II II 00 0 O s to K1 M © ;© § 1 a m to K -a @ CD Esa M E3 This character marked on top circuits indicates 2 No. 14 conductors in J4- inch conduit. Indicates 3 No. 14 conductors in )4-inch conduit. Indicates 4 No. 14 conductors in ^i-inch conduit unless marked inch. Indicates 5 No. 14 conductors in J^-inch conduit. Indicates 6 No. 14 conductors in 1-inch conduit unless marked J^-inch. Indicates 7 No. 14 conductors in 1-inch conduit. Indicates 8 No. 14 conductors in 1-inch conduit. Note. — If larger conductors than number 14 are used, use the same symbols and mark the conductor and conduit size on the run. Feeder run concealed under floor above. Feeder run exposed. Feeder run concealed under floor. Pole line. Push Button. Buzzer. Bell. Annunciator. Interior telephone. Public telephone. Clock (secondary). Clock (master). Time stamp. Electric door opener. Local fire alarm gong. City fire alarm station. Local fire alarm station. Fire alarm central station. Speaking tube. Nurse’s signal plug. Maid’s plug. Horn outlet. District messenger call. Watchman station. Watchman central station detector. Public telephone — PBX switchboard. Interconnection telephone central switchboard. Interconnection cabinet. Telephone cabinet. Telegraph cabinet. Special outlet for signal system. As described in specifications. Battery. Signal wires in conduit. Concealed under floor. Signal wires in conduit. Concealed under floor above. 0 w ijj Copyright 1922-1926, B. B. Barling Bruce, Milwaukee, Publishers 65071 ? Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring GENERAL INSTRUCTIONS FOR SHOP WORK Method of Procedure After Being Assigned to a Job (a) Upon receiving assignment go to your place immediately and work out wiring diagram. (b) Have wiring diagram checked by instructor in charge. (c) Fill out order blank on stock room for material necessary for the job, using trade names and numbers, and after instructor’s O.K., obtain same from stock room. (d) Put up the work according to specifications in as quick and neat a manner as possible. (e) Have problem checked by same instructor who checked the wiring diagram. (f) Fill out time and material blank on the specification sheet, giving current prices on all ma- terials used and time actually consumed in the installation. (g) Take down all work before starting on another job. (h) At the end of your day’s work clean up your place of work, being sure to turn in tool and material box to stock room. Knowledge of Code Rules, speed and accuracy are essential to all good workmen. Upon these points especially will you be graded in your work. Instructor’s Note: The instructor is expected to supplement this course with a discussion of trade methods and rules prevailing in the locality. Copyright 1922-1926, B. B. Burling Bruee. Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring JOB L-l— WIRE CLEANING AND SPLICING Material — No. 14 wire for splices. Wire — The wire used for Light and Power Circuit wiring is Brown and Sharp (B & S) No. 14 or larger. Different insulations are used, depending upon temperature, moisture, and service conditions. The most universally used insulation is a single braid rubber covering (R. C.). National Electrical Code 1925-601b: Must not be of a smaller size than No. 14 B & S gage except as allowed for fixture work and flexible cords. Very often the total current in a circuit is much less than that allowed for a No. 14 wire, but smaller sized wires are not permitted as they do not have sufficient mechanical strength to insure them against breakage. After conductors are in place, shrinkage of timbers and settling of the build- ing will frequently cause a strain on the wires. If the wires were smaller than No. 14 they would not stand this strain without injury. In fixture work where the wires are encased in tubing, smaller sized wires can be used as there is no strain imposed upon them. Pendant or lamp cord should always be exposed and hang freely in the air. No tensile strain other than the weight of a socket and shade is permitted. Skinning — Insulation, where not too heavy, can be loosened by pressure between the handles of the electrician’s pliers. If the insulation is too heavy it can be either pounded or cut loose. In cut- ting the insulation care should be exercised to avoid scratching or cutting the wire. Fig. 1 shows the correct and incorrect way of skinning wires. Where the wire is injured, a break is likely to occur when a stress is applied. Skinning pliers are available, but the majority of tradesmen use other methods. *3 Incorrect Method Correct Method Fig. 1. National Electrical Code 1925-61 lc: Must be so spliced or joined as to be both mechanically and electrically secure without solder. The joints must then be soldered, unless made with some form of approved splicing device, and covered with an insulation equal to that on the conductors. Splicing — After skinning, the conductor should be scraped clean so as to insure good contact. The splices used most frequently are Short Western Union, Rat Tail, and Tap or Branch splice. The methods of making these splices are indicated in Fig. 2. Rot- toil Splice t£nd Turns-'' Short Western Union Splice Method sf Joining Large Cable Fig. 2. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Where Used — The Western Union splice is used most commonly where two wires are to be joined in a line. The branch splice, as the name indicates, is used where a branch is to be joined to a line. The rat tail splice is used to join wires approaching each other from opposite directions, as in con- duit or cable wiring where the splices are made inside of a box or a pot head. Problem Make up two splices each of Western Union, rat tail and branch, and have them inspected by the instructor. Skill and speed can only come through practice. In all of the following problems endeavor to make every splice up to standard. Save these splices for Job L-2. Questions 1. Outside of fixture work and pendant cords, what is the smallest size wire allowable in light and power wiring? Answer 2. How are wires to be joined? Answer 3. How should wires be prepared before soldering? Answer .. 4. What does B and S stand for? Answer : .....' 5. Where are pendant cords used in a house? Answer Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring JOB L-2— SOLDERING WITH AN IRON (COPPER) Material — Wire for splices, suitable flux, salamoniac, soldering iron and wire solder. How to Solder — The neck on the Western Union, the long wrap on the tap splice, and the entire end of rat tail splice must be soldered to insure against loosening of the contact between conductors. It is not necessary to solder the turns that are wound close together. When soldering with an iron, place a little flux on the neck of the splice and heat. Feed the solder into the turns from above as indicated in Fig. 3. The heat of the iron will cause the solder to flow over and between the turns of the splice. Shake off any surplus solder, as it may leave sharp points which will penetrate the tape used to insulate the joint. Problem — Solder with an iron at least one of each of the splices made in Job L-l. Save these splices for Job L-4. Flux — Never use an acid flux on splices of cop- per wire, for it causes corrosion of the copper and weakens the splice. Always have the wires bright and clean before applying flux. A liquid soldering flux recommended by the Underwriters is made as follows : Saturated solution of zinc chloride. .5 parts Alcohol 4 parts Glycerine 1 part The Soldering Iron or Soldering Copper — Always use a soldering iron that is well tinned. To tin, heat the iron sufficiently to melt solder and place in a can of powdered salamoniac or rub on a sal- amoniac stick. This cleans the surface of the copper. Hold a piece of solder against the point. If the iron has been well cleaned the solder will flow over the entire surface. The iron is now ready for use. Never leave an iron on the flame until it becomes red hot, for this will burn off the tinning and oxidize the copper. Problem Retin an iron as described. Copyright 1922. B. R. Burling Bruce. Milwaukee, Publishers Digitized by the Internet Archive in 2016 https://archive.org/details/looseleafshopmanOOburl Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring JOB L-3— SOLDERING WITH A TORCH. Materials — Wire for splices, suitable flux, gasoline blow torch and wire solder. Method — In soldering with a blow torch the insulation of the conductors is nearly always ignited, causing damage to the insulation, unless the wire is skinned farther back from the joint. The insula- tion burns with a dense black smoke and blackens everything with which it comes in contact. The blackening of the splice prevents the free running of the solder and makes soldering difficult. The small alcohol torch gives better satisfaction than the larger gasoline torch. The gasoline torch is not generally used except on large wire where the iron would not be suffi- ciently large to heat the splice. In soldering the joints of splices with a torch remember: 1. Avoid a large flame and the burning of the insulation. 2. Heat the splice until it is hot enough to melt the solder. Never use the torch flame to melt the solder. 3. A cold joint cannot be properly soldered although there might appear to be more than enough solder on the splice. 4. It is not the large amount of solder which makes a good joint, but the proper placement of a small amount. Problem Solder at least one of each of the different splices. The Care of a Gasoline Blow Torch Fill the torch about two-thirds full of GOOD gasoline. This will leave sufficient air space and eliminate frequent pumping. Be sure that the filler plug is tight, and that the check valve in the pump does not permit the escape of air. Common soap rubbed on the threads of the plug will help to prevent the leakage of air. A little lubricating oil occasionally rubbed in the leather washer of the pump will keep it in good working order. When starting a torch fill the drip cup full of gasoline and light. Shield the flame from draft so that the burning of gasoline will sufficiently heat the burner to generate gas. If raw gasoline shoots from the burner or the torch burns with a long yellow flame it indicates that the burner has not been sufficiently heated and the cup must again be filled and burned. Handle the torch carefully and do not move about while burning the gasoline in the drip cup or serious accidents may result. Do not try to work with a leaky torch. When putting out the torch do not turn the needle valve too tight, as it will cause an enlarge- ment of the opening in the burner. After the burner is shut off loosen the needle valve slightly. Due to unequal contraction of burner and needle point, while cooling, the valve may become so tightly closed that great force is required to open it. Copyright 1922. B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring job L-4— TAPING OF SPLICES Materials — Rubber covered wire for splice or splices used in Job L-2, rubber tape and friction tape. National Electrical Code 1925-611c: The splice must be covered with an insulation equal to that on the con- ductors. Problem I — Tape the Western Union splice as follows: 1. Take a piece of rubber tape about two inches long. 2. Begin at bevel marked A, Fig. 4, on sketch, and wrap spirally to the other bevel B. Be sure to have a rubber insulation equal to the rubber on the conductor. Have the tape under tension while wrapping and overlapping each turn half the width of the tape. 3. If the rubber tape does not adhere well, which is generally the case when the tape is old or of inferior grade, apply artificial heat. A Friction Tape Fig. 4. 4. Wrap the joint tightly with two layers of fric- tion tape. Run this tape well back over the braid of the wire. II — Tape the rat-tail and branch splices, using the same general method. Instructor’s Note: It is not possible to cover all phases of wire and cable splicing and taping in this brief text. It is expected that the instructor will expand this and any other topic as he sees fit. National Electrical Code 1925-602g: For conductor sizes No. 8 and smaller the neutral conductor on all 3-wire circuits and one conductor on all 2-wire circuits shall have a continuous identifying marker readily distinguishing it from the other conductors. For rubber-covered wire the identification shall consist of a white or natural gray covering. When one of the circuit wires is to be grounded, the ground connection shall be made to this identified wire. National Electrical Code 1925-611t: When one of the circuit wires is to be grounded, the circuit shall be so ar- ranged that the grounded conductor is the one identified as prescribed in section 602e of this code. The identified wire is shown by a broken line. Copyright 1922-1926. B. B. Burling Bruce. Milwaukee. Publishers CL Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring OPEN WIRING Job L-5— SUPPORTING CIRCUIT WIRES One light controlled by a single pole snap switch (S 1 ). Wire as shown in sketch, Fig. 5, taking special care that all wires are drawn tight. Run all wires straight and parallel with the edges of the board or room. Install all wires before putting on switches and receptacles. Solder and tape all splices. Note Figs. 5, a, b, c, d, e, f, carefully. No. LIST OF MATERIALS COST Unit Total 4 Split Knobs 3 Pair Two Wire Cleats 1 Cleat Receptacle 1 S 1 Switch 1 4" Porcelain Tube 6 2" No. 9 Screws 1 Switch Base or Block Wire Screws for Switch and Receptacle TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Split Knob nr - — rn c# m Cleqf Cleat Assembled ir < 4r <> /■■HK / » 1 X / 1 » \ a 1 1 [ J T i\ i> Knob . Moil end Leather Head Fig. 5a. Cleat Receptacle Fig. 5c. Cleats qnd Screws When screws are used leather heads' mo y be omitted Switch -block Fig. 5e. Noils ond Leather Heads used with cleats- Fig. 5b. Sin g le Pole 5nap Switch Fig. 5d. Switch mounted on block Cut or break wire close to bindin g screwy Method of fastenin g wire under bindin g screw. Fig. 5f. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring OPEN WIRING Rules Regarding the Supporting of Circuit Wires National Electrical Code 1925-501a: Supports shall be com- posed of approved non-combustible, non-absorptive insulating material, free from checks, rough projections or sharp edges which might injure the insulation on the conductor. If the supports are designed to grip the wires, either screws or nails may be used to fasten the supports in place, but nails shall be long enough to penetrate the wood- work not less than one-half the depth of the knob and fully the thickness of the cleat. Cushion washers shall be used with nails. In the supporting of knobs and cleats either screws or nails may be used, although there are cases in which only screws can be used. If knobs or cleats are to be fastened to a thin piece of wood screws must be used because nails will not hold the insulators securely in place. When screws are used, care must be taken not to draw them up too tightly as they are liable to crack the knob or cleat Knobs and cleats that have been in place for some time frequently break and lose their grip on the con- ductor, because of the expansion caused by heat or swelling of the wood due to moisture. When nails are used, leather washers or “leather heads” must be used to prevent injury to the knobs or cleats. See Figs. 5a and 5b. These leather heads are usually punched from scrap leather and run very uneven in thickness, so enough washers must be used to make the thickness of the pro- tection at least one-eighth of an inch. Knobs may now be obtained with leather heads and nails as- sembled. Questions 1. How are wires protected when crossing water or gas piping? Answer 2. What kind of knobs are used for wires smaller than No. 8 B and S? Answer 3. How should knobs and cleats be fastened? Answer 4. Where nails are used, how is the porcelain protected? Answer 5. Why is it so necessary to prevent moisture from coming in contact with the wires? Answer 6. Should wires be strung under piping? Why? Answer 7. How are the ends of a run secured? Answer 8. Is friction tape sufficient insulation on a splice? Answer 9. State the rule governing the insulation to be used on a splice. Answer Rules Regarding the Supporting of Circuit Wires National Electrical Code 1925-611-91h and i: Where not en- closed in approved conduit, raceways or armored cable and where liable to come in contact with gas, water or other metallic piping or other conducting material, must be separated therefrom by some continuous and firmly fixed non-conductor creating a permanent separation. Must not come nearer than two (2) inches to any other electric lighting, power or signaling wire, not enclosed as above, without being permanently separated therefrom by some continuous and firmly fixed non-conductor. The non-conductor used as a separation must be in addition to the regular insulation on the wires. Where tubes are used they must be securely fastened at the ends to prevent them from moving along the wires. In open wiring where wires cross gas or water pipe, or other metallic conductors, they must be separated therefrom by some non-conducting material. Porcelain tubes are generally used. These are slipped over the wires and fastened securely in place. These may be held in position by placing a split knob or cleat at each end of the tube, as shown by Fig. 6, or by taping the tube securely to the wire, as shown by Fig. 7, or sometimes to the pipe. Sometimes non-metallic flexible tubing is used where not exposed to moisture. Where wires cross, the best and usual method of separation is to place a tube on one of the wires. This tube should be placed on the wire nearest to the surface wired over and held in position as illustrated by Fig. 7. This will prevent either wire from coming in con- tact with wall or ceiling. Where wires are two inches or more away from a pipe, no additional insu- lation is necessary, although it is better to put a tube on the wire at the cross-over, because the wire may sag or become loose and thus come directly in contact with the pipe if no other insulation is pro- vided. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling: Vocational Series Light and Power Wiring Split Knobs; porcelain tube taped to wire to hold it in place. Water Pipe Wires Crossing Fig. 6. Fig. 7. National Electrical Code 1925-501g: Must be so installed in wet places that an air space will be left between con- ductors and pipes in crossing, and the former must be run in such a way that they cannot come in contact with the pipes accidentally. Wires should be run over, rather than under pipes upon which moisture is likely to gather or which, by leaking, might cause trouble on the circuit. Where wires cross a water pipe or other conductor in wet places, a separation of at least 2" should also be provided. If it is impossible, a porcelain tube should be placed on the wire and the wire run over rather than under the pipe so as to prevent moisture coming in contact with the wires. (See Fig. 6.) If it is absolutely necessary that the wires run under the pipe a tube should be placed on the wire in addition to the 2" separation. National Electrical Code 1925-501-CS Open dry places: — Must not be deadened at a rosette, socket or receptacle unless last support is within 12-inches of same. In open work never terminate (deadend) a wire at an outlet unless there is a support within at least 12" of the same. This is to relieve the rosette or socket of any strain which may be on the wires. If there is no support within 12" of the rosette, the wires may be continued beyond the rosette and deadended at a knob or cleat in the manner shown by Fig. 8. ,Less than 12” _ ' — — >■ Fig. 8. Copyright 1922-1926, B. B. Burling Bruce. Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-6— OPEN WIRING One light controlled by double pole single throw (D.P.S.T.) knife switch. 4 — 4 5 — -Q » Ne. LIST OF MATERIALS COST Unit Total • TIME REQUIRED TOTAL GRADES Time Workmanship Book Record , Average. . . Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Additional Rules Governing Open Wiring National Electrical Code 1925-501 j: Conductors of size No. 8 B and S gage or over used in connection with solid knobs must be securely tied thereto. If wires are used in tying they must have an insulation of the same type as the conductors they confine. Insulators for the supporting of wires are usually made of porcelain. As we are now dealing only with branch circuits, we will take up the types of supports used on wires smaller than No. 8 B & S. In the support of these smaller wires split-knobs or cleats should be used. The tie-wire method of supporting these smaller conductors has not proved satisfactory, for the tie-wires shear off the con- ductors when not put on carefully and may also untwist and allow the conductors to fall away from their support. The split knobs and cleats clamp the wires securely and hold them in place permanently. National Electrical Code 1925-501k: Open dry places: — Must be rigidly supported on non-combustible, non- absorptive insulators, which will separate the wires from each other and from the surface wired over in accordance with the following table: Voltage Distance from Surface Distance between Wires 0 to 300 One-half inch Two and one-half inches 301 to 500 One inch Four inches Rigid support requires under ordinary conditions where wiring along flat surfaces, supports at least every four and one-half feet. If the wires are liable to be disturbed, the distance between supports must be shortened. In buildings of mill construction, mains of not less than No. 8 B and S gage, where not liable to be disturbed, may be separated about six inches and run from timber to timber not breaking around and may be supported at each timber only. All wires on systems not exceeding 300 volts must be kept at least one-half inch from the surface wired over and be separated at least two and one-half inches. Wires are generally supported on stand- ard knobs or two-wire cleats, which are now manufactured to comply with above specifications. In running wires on a straight surface they must be supported at least every four and one-half feet, but if there is a chance of the wires becoming loose, or if they run near belts, shafting, etc., the supports must be brought closer together. In mill constructed buildings where wires smaller than No. 8 are used they must break around the timbers as shown by Fig. 9. If run directly from timber to timber, small wires must be supported on run-boards, as illustrated by Fig. 10, or protected by guard strips placed on each side of the wires. Small wires breakin g around timbers Fig. 9. Question 1. Where is such a system used? Answer No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record . Average. . . Copyright 1922. B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-12— OPEN WIRING Installation of entrance cut-out on an open loop system. Each light individually controlled by a single pole (S') snap switch. <><><><> o°~r Questions 1. What is an open loop system of wiring? Answer 2. Why are the fuses placed as they are on the entrance switch? Answer No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time , Workmanship Book Record . Average. . , Copyright 1922, B. B. Burling Bruce. Milwaukee, Publisher Q c Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-13— OPEN WIRING Two point control using single pole double throw (S.P.D.T.) knife switches. (Use split knobs.) o ; <> <> Note: Where the current controlled is greater than the law would allow with snap switches, knife switches can be used. No. LIST OF MATERIALS COST Unit j Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922. B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-14— OPEN WIRING Three point control using two three-way (S’) snap switches and one four-way (S 4 ) snap switch. s* s 3 © © - 0 - - 0 - Question 1. Where is such a system used? Answer No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . Copyright 1922, B. B, Burling Bruce, Milwaukee. Publishers ' . 1 • < : : ' Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-15— OPEN WIRING Installation of entrance cut-out on a closed loop system. Each light individually controlled by single pole (S 1 ) snap switches. ■0" -O' -0- -0- O Question 1. What is a closed loop system? Answer No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-16— OPEN WIRING Three point control using two three-way (S’) snap switches, and one double pole double threw (D.P.D.T.) knife switch. m s s 3 0 - <> <> Note: This problem is introduced to show how an S‘ snap switch on Job L-14. to connect a D.P.D.T. switch to serve the same purposes as No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-17— OPEN WIRING Two point control using two double pole double throw (D.P.D.T.) knife switches. Both sides of the line run to the switches. s a s a ■O' "0" ■O’ Question 1. What advantage has such a system over that used in Job L-13? Answer No. LIST OF MATERIALS ; COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright, 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L- 18 — OPEN WIRING Four point control using- two three-way (S“) and two four-way (S 4 ) snap switches. <> <> Questions 1. Where is such a system used? Answer 2. In a six point control system, how many S* and how many S 3 switches would be used? Answer No. LIST OP MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Burling Vocational Series Loose Leaf Shop Manual Light and Power Wiring Job L-19— OPEN WIRING Three point control using two single pole double throw (S.P.D.T.) and one double pole double throw (D.P.D.T.) knife switches. S 13 Cj O— j -0- -Q- -0- -0- -0- No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record . Average. . , Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Mannal Burling Vocational Series Light and Power Wiring Job L-20— OPEN WIRING Three point control using two double pole double throw (D.P.D.T.) and one four pole double throw (4 P.D.T.) knife switches. Both sides of the line run to these switches. ■O' ■0’ "O' ■O' -0- No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average . . , Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-21— OPEN WIRING Two point control using two four-way (S 4 ) snap switches. Note: In case of emergency S‘ switches may be used in place of the regular S* switches. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-22— OPEN WIRING Upper and lower hall lights controlled respectively by three-way (S 3 ) switches on first and sec- ond floors. Z n * fl oor <> \ floor " Q z LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-23— OPEN WIRING Four point control using one S 3 snap switch, one D.P.D.T. knife switch, one S* snap switch, and one S.P.D.T. knife switch. ■0 - "O' ■0' ■O' Note: In case of emergency a D.P.D.T. switch may be used in place of an S* snap switch and a S.P.D.T. switch in place of the regular S 3 snap switch. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record , Average. . , Copyright 1922, B. B. Burling Bruce, Milwaukee. Publishers . . . I .Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-24— OPEN WIRING Two point control of a three wire system using knife switches. <><><><> "0" "O’ O’ "0" No. LIST OF MATERIALS COST Unit Tota* TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922-1926. B. li. Burling Bruce. Milwaukee, Publishers Leose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-25— OPEN WIRING Electrolier lighting system; where one electrolier (S E ) will control lights on one, two or three circuits. Show internal connections of the switch in each position and put up both types: 1, 2, 3, and 1, 1 and 2, 1 and 2 and 3. Q Q Q Q * 2 <3 off © © o o 1 1*2 1,2*3 off Question 1. Where are electrolier switches used? Answer No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers "O' "O' "O' ■ . ■ ■ Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-26— OPEN WIRING A lighting system for photographic developing room to be controlled by two switches, a single pole (S 1 ) and three-way (S s ) snap switch. The operation of the three-way switch is to throw on the red or white light as desired. White No. LIST OF MATERIALS COST Unit Total • TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-27— OPEN WIRING This problem has been purposely omitted from the students’ manual, inasmuch as this system does not comply with the present National Code Rules. In trade classes, this problem might find a place, inasmuch as there are such systems still in use. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L- 28 — OPEN WIRING Standard master switch control using a single pole (S 1 ) switch for the master. Individual lights to be controlled by three-way (S s ) switches. A <> o ■O' Questions 1. Where can a master switch be used to advantage in a residence? Answer 2. What is the object of its use? Answer No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling; Vocational Series Light and Power Wiring Job L-29— OPEN WIRING Double control of a circuit. Lights so connected by means of two single pole (S 1 ) and one double pole (S J ) switch that two parts of the circuit may be controlled separately or simultaneously. © - 0 - - 0 - - 0 - Qy © <> <> - 0 - No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-30— OPEN WIRING Two point control of a circuit with the addition of a single pole master switch. o o Note: The use of a master switch in connection with a stair lighting system is of advantage in case of a night alarm. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . Copyright 1922, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-31— OPEN WIRING Lighting circuit including two point control of hall light with the addition of a master control switch (S‘) which can light all the lights in case of emergency. (§) <> <*> <> Hall Light Q) o © © <> Note: In case of emergency, it is not only desirable but necessary to be able to flash on all the lights in a house by one master switch. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADE9 Time Workmanship Book Record Average. . . Copyright 1922. B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-32— OPEN WIRING Five lamp 600 volt series street car lighting circuit controlled by one single pole snap switch. A three-way (S 3 ) switch is used as a transfer switch to turn on head light and platform light as desired. Trolley © -Q- -C>- -0- - 0 - Platform Li g ht ■O' Head Li ght Note: It is quite customary to have the rear platform light and the front head light on at the same time. The rear head light and the front platform light will be dark. No. LIST OF MATERIALS COST i Unit Total TIME REQUIRED TOTAL GRADE” Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers ' ' ■ . Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring CONCEALED KNOB AND TUBE WIRING Knob and tube wiring, the cheapest of all methods, is still extensively used in smaller cities. Most of the larger cities now prohibit this system. It has its disadvantages from a fire standpoint in that the wires are not well protected. Tubes may break, knobs come loose, and thus allow the conductors to get out of place. Wiring Plan: The term “wiring plan” as often used in electrical work is the floor plan of a building showing the location of light, power and appliance outlets with the location of their respective control- ling devices. Routing Plan: A routing plan is the floor plan of a building showing not only the location of outlets but also the complete layout of the actual run of wires between said outlets. Secure the latest revision of the National Electrical Code and note any modifications or changes in the rules governing the subsequent jobs. National Electrical Code 1925-502: Concealed Knob and Tube: — Must be rigidly supported on non-combustible, non-absorptive insulators which separate the wires at least one inch from the surface wired over. Should prefer- ably be run singly on separate timbers or studdings, and must be kept at least five inches apart. Must be separated from contact with walls, floor timbers and partitions through which they may pass by non- combustible, non-absorptive insulating tubes, such as glass or porcelain. Wires passing through cross timbers in plastered partitions must be protected by an additional tube extending at least four inches above the timber. Rigid supporting requires under ordinary conditions where wires run along flat surfaces, supports at least every four and one-half feet. If the wires are liable to be disturbed the distance between supports must be shortened. At distributing centers, meter outlets, switches or other places, where space is limited and the five inch separa- tion cannot be maintained, each wire must be separately incased in a continuous length of approved flexible tubing. The ordinary cleat used for small wires cannot be used in this class of work for it does not separate the wires one inch from the surface. Split knobs should be used and the wires kept at least five inches apart, as shown by Fig. 13, to prevent any possibility of the wires touching each other. It is better to run the wires on separate timbers, as illustrated by Fig. 11. lA/ires on separate timbers' Fig. 11. Fig. 12. Fig. 13. Where wires pass through joists, studdings or partitions the wires must be insulated with porce- lain tubes. A 3" x 5/16” tube is the standard in ordinary house wiring. This allows a y 2 " projection on each side of 2"x4”, Fig. 12. Where wires pass through plates at the head of the partition an extra tube must be placed on the wire to prevent the wet mortar coming in contact with wires while plastering. Where running along a flat surface the wires must be supported at least every four and one-half feet and if there is any possibility of the wires being disturbed the supports should be brought closer together. In a place where a large number of wires are brought to one central point, as at a distribu- tion cabinet or meter outlet, the five inch separation cannot be maintained. In this case each wire must be encased in an approved non-metallic flexible tubing. This insulation must be in one piece and not in short lengths, as the lengths of tubing may separate and leave the wire unprotected. Copyright 1U22-1926, B. B. Burling Bruce, Milwaukee, Publishers ■ •• ' ... ■' ' . . . ' : . ' < - ' .. Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-33— CONCEALED KNOB AND TUBE WIRING Wire for one ceiling and one bracket outlet. Ceiling outlet to be controlled by a single pole (S 1 ) snap switch. Routing Plan ¥ZZZZZZZZZZZZZZZZZZ \ 77 a o VZZZZZZZZZZZZZZZZZZZA TZZZZZZZZZZZZZZZZZi No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922-1926, B. B. Burling Bruce. Milwaukee. Publisher* Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring National Electrical Code 1925-502h: Must at all outlets except where conduit is used, be protected by approved flexible tubing, extending in continuous lengths from the last porcelain support to at least one inch beyond the outlet. In the case of combination gas and electric outlets, the tubes on the wires must extend at least flush with the outlet ends of gas caps, and if box or plate is used, gas pipes must be securely fastened into outlet box or plate to secure good electrical connection. When the surface at any outlet is broken, it must be repaired so as to leave no holes or open spaces at such outlets. At outlets in concealed knob and tube work, each wire must be encased in non-metallic flexible tub- ing extending from the last support to at least 1" beyond the surface (Fig. 14). If there is a gas pipe at the outlet the flexible tubing must extend so as to be at least flush with gas cap (Fig. 15). At a gas outlet the tubing may be tied to the gas pipe so as to be held securely in place. All open- ings at outlets, such as broken plaster, must be repaired to prevent a flash between conductors from igniting combustible material in a concealed place. It is suggested that approved outlet boxes or plates be installed at all outlets in concealed knob and tube work. The wires should be protected by approved flexible tubing, which extends in a continuous length, from the last porcelain support, into the box. Metal (loom) bushings are used in such wiring installations to secure the tubing. Two types of bushings are shown in Fig. 16, one with $4", and the other with Yz" openings. Sharp ed g e which dri ps*' loom' 1 ^ Groove, to fit in opening N^l Universal Bushin g for s /&o penin g s Groove- to fit in openin g Ed g e which gri ps'loonf N- 2. Universal Bushin g for open in gs ^ Steel o utlet box * ^Bushin g N a 2. Universal bushin g in place Fig. 16 . Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-34— CONCEALED KNOB AND TUBE WIRING Wire for one ceiling outlet controlled from two points. One bracket and one base plug outlet. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record , Average. . , Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-35— CONCEALED KNOB AND TUBE WIRING Wire for one ceiling outlet controlled from three points. Two bracket outlets each controlled by a single pole flush switch. One base plug outlet. Routing Plan WZZZZZZZZZZZZZZZZZZZZ& s' <> 1 {] Oi £ “ 0 " © Y&ZZZZZZZZZZZZZZZ A No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. , Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers - Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring WOOD MOLDING Wood molding is a cheap method of surface wiring used frequently to extend a circuit in existing installations. Its use is, however, limited to dry places and is not permitted in elevator shafts or where there are fumes. Many of the larger cities have prohibited its use entirely. Togg le- bolt Molding End view of Wood Moldin g Protection for moldin g and tubes where circuit passes thru floor. Porcelain Tubes Fig. 17. Fig. 18. Fig. 19. National Electrical Code 1925-504a and b: Must never be placed in either metal or wooden raceways in damp locations; must never be placed in either metal or wooden raceways, in concealed locations or where the difference of potential between any two wires in the same system is over 300 volts. Wood molding should not be placed directly against brick or concrete as the wall is likely to sweat and thus introduce moisture back of the molding. This warps the molding and may also cause a leak- age of current between the wires, charring the wood and starting a fire which would not be discov- ered very readily. If installed on brick or concrete, backing blocks should be placed between molding and wall so as to provide an air space. The object of wood molding is to protect the wires against mechanical injury and to conceal the wires from view. The molding where placed against plastered walls should be fastened with lj4" No. 8 flat head wood screws. When placed on wooden walls, nails may be used. On brick or concrete, the wall is drilled and plugged with wood, and the molding fastened thereto with screws. In hollow tile construction, the toggle bolt shown by Fig. 17 may be used. The capping is supported by small nails or brads carefully driven so as not to injure the wire insulation. Nails should never be used to hold the wires in the grooves of the molding. The groove, as is shown by Fig. 18, is shaped so as to hold the wire. If circuits are to be run through floors, run the molding to within 4" of the floor and continue the circuit to the ceiling below in porcelain tubes. Protection or “kick blocks” must be provided at the floor to protect the molding from moisture and in- jury. See Fig. 19. At turns the molding and capping should be mitered, as shown in Fig. 20, to make a neat looking job. Never make a splice or tap in wood molding, but use approved fittings, such as are shown in Figs. 21, a, b, c, d, e, f and g. Wooden moldin g mitered at turn Wood Moldin g Tfoplet Fig. 20. Fig. 21a. Copyright 1922-1926, B. B. Burling Bruce. Milwaukee, Publishers Fig. 21b. Loose ueat Shop Manual Burling Vocational Series Light and Power Wiring Fig. 21f. Rotary Surface Snap Switch. Fig. 21g. Sub-base for Snap Switch. Job L-36— WOOD MOLDING Mitre Box Make a mitre box for use in the other problems in wood molding. (a) Select a straight piece of 2"x4" and cut off 24". (b) Nail on two side pieces of 1" x6" lumber as shown in Fig. 22. Fig. 23. (c) With a square mark off lines aa and ab. (d) In the same manner mark off c' c" and d' d" in the relative positions indicated on Fig. 22. (e) From d' and c' measure off as indicated distances equal to d' d" and c' c" respectively. These points are marked d and c respectively. (f ) With a square mark off dd, d" d", cc and c" c". (g) Saw down the lines ddd" d", ccc" c" and ab ab. The cut ab ab is used for a “square” or 90° cut. The cuts ddd" d" and ccc" c" are used for 45° cuts. See Fig. 23. Job L-36-a— WOOD MOLDING Secure some short lengths of two wire molding and make a surface 90° L, an exterior 90° L an interior 90° L, and a T mitre joint. Check each with a square. Time Workmanship Book Record Average . . . Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-37— WOOD MOLDING Wire for one ceiling, one bracket, and one base receptacle outlet. Ceiling outlet to be controlled by single pole (S 1 ) snap switch. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record . Average. . , Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers d' a Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-38— WOOD MOLDING Wire for two ceiling, two brackets and one base receptacle outlet. One ceiling outlet to be con- trolled by a single pole (S 1 ) snap switch. Other ceiling outlet by two three-way (S’) snap switches. Base outlet to be controlled by (S 1 ) switch and located directly below one of the brackets and above the base outlet. Routing Plan No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922. B. B. Burling Bruce, Milwaukee. Publishers ‘ Lioose Leaf Shop Manual Burling Vocational Series Light and Power Wiring METAL MOLDING Metal molding, Fig. 24, is used for surface wiring to extend a circuit, change location of fixtures and in new installations in old buildings where the wires are to be concealed from view, and appear- ance is a factor. E 5 Base t Capping Fig. 24. ■ = 7=1 i. Base and Co pping National Electrical Code 1925-504h and g: (Metal Raceways) When the electrical construction is being carried out in metal raceways, permission will be given to extend these raceways through walls and partitions if the raceways are in continuous lengths where passing through the walls and partitions. Not more than four No. 14 B and S gage rubber covered wires and no single circuit of more than 1,320 watts shall be used in metal raceways. Must for alternating current systems, if in metal raceways have the two or more wires of a circuit installed in the same raceway. Metal molding as made by the National Metal Molding Co., of Pittsburgh, Pa., consists of a chan- nel base over which a channel capping is snapped. It is furnished in lengths of S' A" and is sheradized to prevent rusting. On account of its mechanical strength and the small space it occupies, it is admir- ably adapted for show window and show case installations. Metal molding, where carried through walls and partitions, must be in one piece. When carried through floors an iron pipe extending from the ceiling below to at least 5" above the floor should be provided to insure against moisture and mechanical injury. Metal molding as well as all metallic wire ducts must be permanently grounded and so installed as to form good electrical contact between adjacent parts. Where the installation consists of several parts all must be bonded together by a good conductor or each grounded separately. Suitable fittings are manufactured to connect adjacent lengths, to hold capping in place, and to provide for taps, crosses and outlets. Wire splices should be made only where fittings are provided. Cuttin g with hack-saw Cuttin g with file. File notch dee ply cmd break Fig. 25. Fig. 26. Fig. 27. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Installing an Electrical Circuit usually comprises three operations, namely: (1) tapping circuit at some point, (2) carrying it to some other point, (3) installing a device at the new location. Before these operations can be properly performed, it is necessary to have a general idea of the construction of the molding which is to be used and of the methods of cutting, bending and supporting it. The methods of cutting are shown in Figs. 25, 26, 27. If much work is done, the shear will quickly pay for itself by the time it saves. With file or shear, base and capping are cut separately ; with a hack saw they may be cut together. Use a fine tooth hack saw, coarse blades will crack. Punch Fig. 28. Where molding is cut it is usually necessary to provide key- hole slots at the new ends and to punch additional supporting holes. This is done with a specially designed tool. Fig. 28. Metal molding can be mitered for elbows by cutting with a hack saw, Fig. 29. These mitered elbows have the advantages of appearance and continuity. Base Mitered Capping Mitered \ t £3 | Mitered Elbow Assembled Fig. 29. Job L-39— METAL MOLDING 1. Obtain some short pieces of used metal molding (base and capping), a fine toothed hack saw. a three or four cornered file and a miter box. Cut and miter at least one sample for inspection, (a) using the hack saw and one (b) using the three or four cornered file, (a) Time Bendin g metal moldin g with the aid of g g uide. (b) Time 2. Bend a short length of metal molding, with capping in place, as shown in 30a around a 4" radius. Time 3. Bend a short length of metal molding, with capping in place, as shown in 30b for a 4" offset. Time Fig. 30a. Fig. 30b. GRADES Time Workmanship Book Record Average. . . Copyright 1922-1926. B. B. Burling Bruce. Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-40— METAL MOLDING Wire for one ceiling, one base receptacle and three bracket outlets. Each bracket outlet controlled by an S 1 switch placed directly below. Ceiling outlet controlled from two points. Routing Plan No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring A method of holdin g base and ca pping Caution Do not ruthlessly hammer the capping, as this will cause it to spread and not grip the base. When the capping does not fit se- curely use straps, Fig. 31. When a receptacle is installed at the end of a run the molding enters the base from one side only. Fig. 35. When installed in an intermediate position the molding appears to enter from both sides, although in reality the base of the molding is continuous and only the capping is cut. Fig. 36. When the addition of a recep- Method of usin g 9Q o qnd45 0 Flat Elbows , also Internal and External Elbows Fig. 32. Methods of usin g Tee Fittin gs Fig. 33. Methods of usin g Crosses Fig. 34. Receptacle on a throu g h run Method of installing receptacle at end of run. Fig. 36. Fig. 35. Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L- 41 — METAL MOLDING Wire for four ceiling outlets controlled by pull switches. Each switch is to control three lights. This system may be used as general lighting in a store. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922-192G. I',. B. Burling Bruce. Milwaukee. Publishers fj i Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-42— METAL MOLDING Wire for one ceiling, two bracket, and two base receptacle outlets. Ceiling outlet to be controlled from two points. Each base receptacle to be controlled by an S 1 snap switch. Routing Plan No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average, Copyright 1922, B. B. Burling Bruce. Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Common methods of supporting metal molding are shown below. Figs. 37, 38, 39. The spring head toggle bolts, E and F, Fig. 38, cost less than ordinary toggle bolts. As seen in the sketch, they are also easier to install. The spring heads of these bolts can be easily driven through the support- ing holes in the molding, and through a 7/32" or Y\' hole in the tile or sheet metal, by a slight tap with a hammer. The prongs then spring out and prevent the head from being withdrawn. jVWood B-Bfick or Concrete Q Plaster on Wood jS Wood Screw li Long |x pan ?l on shield is driven. Loth. #SW -Screw ik'Loiw inlo j hole 1 deep and 3 tl* #8 .screws used as for wood Fig. 37. D--P1 aster on Metal Togg le Bolts g’or U E= Tile., with or without Plaster S prin g -head To gg le-bolts or Ordinar y Togg le- bolt-3 ma y also be used- Fig. 38. F s Sheet Metal S prin g -head To gg le-bolts or Ordinar y Togg l e- bolts Ground wire attached to metal molding Fig. 40. Fig. 39. Where metal molding is connected to an existing conduit, or armored cable system, the molding is grounded through the existing system without special effort. Where it is not connected in this way, a ground wire must be used. The convenient way of connecting a ground wire is with the fitting shown by Fig. 40. This fitting has an upturned lip, as shown, into which the ground wire can be soldered. Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring RIGID CONDUIT Rigid iron conduit wiring is approved for both exposed and concealed work. Some cities now re- quire that all concealed wiring shall be in rigid conduit. This system of wiring is coming into use more and more for all classes of work. The use of rigid conduit has resulted in the standardization of various accessories and fittings, enabling the installation of a neat, safe job without much trouble. We£(?W(f/re»j/ INSPECTED f conduit /U»B0l?MOR\tS\ Rigid Conduit Fig. 41. National Electrical Code 1925-503b: No conduit small- er than ^-inch electrical trade size shall be used. It has been found in practice that two No. 14 B and S gage wires cannot be readily drawn through piping smaller than ^ 2 -inch. National Electrical Code 1925-503d: All elbows or bends must be so made that the conduit will not be in- jured. The radius of the curve of the inner edge of any elbow not to be less than 3j4 inches. Must have not more than the equivalent of four quarter bends from outlet to outlet, the bends at the outlets not being counted. All conduit should be marked with the Underwriters’ stamp. Fig. 41. When bending rigid conduit care must be taken not to injure the conduit. If too short a bend is attempted the conduit is liable to flatten or open at the seam. There are many devices on the mar- ket for bending conduit, but the great disadvantage of these devices is that the conduit must be brought to them to be bent and much valuable time is lost. They can be used to advantage only on large jobs where a large number of bends are to be made alike and all can be made at one time. For this reason a very simple but efficient home-made device known as the “hickey,” Fig. 42, can be made. This is made of an ordinary one inch pipe and T fitting. There are also commercial forms of “hick- eys” manufactured, Fig. 42-a. By means of these “hickeys” the conduit may be bent on the job as required. For bending the large size conduits a heavy substantial support must be provided. Such a device is shown. Fig. 43. 1" Tee-* nJ TPipe Home-made' hickev" h=A Fig. 42. JDevice for bending Lar g e size conduit Fig. 42a. Fig. 43. In all conduit work it must be remembered that the conduit is to protect the wire. The insu- lation on the wire must not be injured by coming in contact with the sharp edges of the conduit. This can be overcome by reaming the ends of the conduit. A reamer as shown by Fig. 44 can be used with a brace for all sizes of pipe up to and includ- ing 1". For larger conduits a half round file may be used. Reamer To cut conduit use a hack saw or a cutter which leaves a square edge on the pipe. Fig. 44. Copyright 1922-1926, B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-43— RIGID CONDUIT (a) Secure some pieces of scrap y 2 ” and Y\" conduit and cut off with a hacksaw to 8" lengths. Set the hacksaw blade so that it will cut on the forward stroke. Do not try to make it cut on the return stroke. Use the reamer after cutting. (b) Thread the 8" lengths one inch back from each end. Use “lard oil” or some cutting com- pound. The work will be much easier and the cutter will last much longer. (c) Secure some lengths of >4" used conduit about 3' long. With the use of a “hickey” bend to conform to a chalk mark on the floor. Fig. 45. Fig. 45. Time required to f cut . . . -! thread [bend . . pipe. HOW TO BEND PIPE Mark off on the conduit as many inches as the length of the bend is to be. Set “hickey” about 3J4" from mark, as shown in Fig. 45a, and proceed to bend the measured end up until an angle of about 45° is reached. Next check the bend with a rule to determine whether bend is going to be long or short. If too long move the “hickey” further from mark and proceed to complete the bend. If the bend is going to be short, move the “hickey” nearer the mark before completing the bend. The different steps necessary to make a 90° bend are shown by Figs. 45b, 45c, 45d and 45e. N? 1. Position for Preliminary ©end Hickey- Marh on Conduit > I 'TT 2 Fig. 45a. ^ Measured End-* or Length of 3end m z* Position of Hickey After Preliminary First Bend Fig. 45b. m 5 . Position < f Hickey "When Bend is Finished [zzzz ^ : Fig. 45e. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-43a— CONDUIT BENDING When the measured end is not the end to be bent up the method of procedure is somewhat differ- ent. Instead of setting the “hickey” about ZyY' from the mark it is placed right at the mark. If after checking the bend, it is found that the measured end is going to be too long, the “hickey” is moved nearer the measured end, and if too short the “hickey” is moved away from the mark and the bend is completed as shown in Fig. 45f. Problem Secure some lengths of J4" used conduit about 4' long. Measure off 3' for end on the floor as indicated in Fig. 45f. With the use of a “hickey” bend a 90° or right angle el- bow. Time Workmanship Book Record Average Job L-43-b— CONDUIT BENDING Make all of the bends as shown below and have the same conform as near as possible to the given dimensions. No. 1. 8" offset. Time required No. 2. Bend around a 10' beam. (Make the bends at A and B first and then the two at C and D.) No. 3. Bend around a 2" pipe. (Begin at A, making this bend first, and then finish by making the bends at B and C.) Time required Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers Loose Leal' Shop Manual Burling Vocational Series Light and Power Wiring No. 4. Goose Neck. Bend the round part first and then finish by bending at A. No. 6. Compound quarter bend (right). (Bend the 8" length first, then the 14" and finish with the other 8" length.) Time required 8“-H D T C\2 i No. 7. Compound quarter bend (left). (Proceed as with No. 6.) Time required GRADES Time Workmanship Book Record Average . . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publisher* Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-44— RIGID CONDUIT Wire for one ceiling and one bracket outlet. Ceiling outlet to be controlled by a single pole (S 1 ) flush switch. (Concealed work.) '^ zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz , c I < cu bD c • H 4 -» 3 o K n s‘ m l < 2zzzzzzzzzzzzzzzzzzf VZZZZZZZZZZZZZZZZZZd No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light aud Power Wiring National Electrical Code 1925-503e: Must be continuous from outlet to outlet or to junction boxes or cabinets, and the conduit must properly enter and be secured to all fittings and the entire system must be mechanically se- cured in position. In case of service connections and main runs, this involves running each conduit continuously into a main cut- out cabinet or gutter surrounding the panel board, as the case may be. For surface extensions from existing outlets in concealed conduit work, an outlet box, extension ring, or blank cover must be mounted over the original box and electrically and mechanically secured to it. Conduit, ar- mored cable, metal raceways or wires must be brought through suitable openings in extension box, ring or blank cover. The piping must run continuous from outlet to outlet in order that the wires may be easily drawn in after the conduit system is completed and also that they may be withdrawn from it at any time with- out injury to them. It also insures that the wires are protected throughout their entire length. National Electrical Code 1925-503g: Metal conduits where they enter junction boxes and at all other outlets, etc., must be provided with approved bushings or fastening plates fitted so as to protect wires from abrasion, except when such protection is obtained by the use of approved nipples, properly fitted in boxes or devices. ® Every run of conduit must terminate at an accessible steel outlet box or plate with a locknut and a bushing, shown by Fig. 46, which have a conductive coating to secure better electrical contact throughout the system. The bushings prevent the insulation of the wires being injured. Lock-nut Bushing Fig. 46. National Electrical Code 1925-503e: Must be first installed as a complete conduit system, without the con- ductors. The conduit system should first be installed complete and then the conductors drawn in. This is to prevent injury to wires while bending conduit and also to prevent wires being so installed that they cannot be readily withdrawn at any time. Must be equipped at every outlet with an approved outlet box or plate. In complete installations the box or plate must be covered by an approved cover or fixture canopy. At exposed ends of conduit (but not at fixture out- lets) where wires pass from the conduit system without splice, joint or tap, an approved fitting having separately bushed holes for each conductor must be used. Outlet plates must not be used where it is practicable to install outlet boxes. For concealed work in walls and ceilings composed of plaster or wooden joist or stud construction, outlet box or plates and also cutout cabinets must be so installed that the front edge will not be more than y^-mch back of finished surface of the plaster, and if the surface is broken or incomplete it shall be repaired so that it will not show any gap or open space around the edges of the outlet box or plate or of the cutout cabinet. On wooden walls or ceilings, outlet boxes or plates and cutout cabinets must be so installed that the front edge will be either flush with the finished surface or project therefrom. This will not apply to concealed work in walls or ceilings composed of concrete, tile or other non- combustible material. In buildings already constructed where the conditions are such that neither outlet box nor plate can be installed these appliances may be omitted, providing the conduit ends are bushed and secured. Copyright 1922-1926, B. B. Burling Bruce. Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Sing le, box for switch or receptacle. Sin g le s pacer to make gout} boxes Single box for Gan q _ £> Q .jl use in shallow wol/s Fig. 47. Steel outlet boxes and plates, a number of which are shown in Fig. 47, should be installed for sev- eral reasons. First, to provide a continuous metallic protection for the wire ; second, to provide a sup- port for the fixture ; third, to provide a continuous electrical path for grounding the conduit system. Outlet boxes should be used in preference to plates because they give more space in which to make splices and taps. Boxes must be installed at switch outlets and where receptacles are to be used. The plates may be used where fixtures with canopies are going to be installed. The canopy provides a space for splices and taps. At drop cord outlets a box with cover and bushed openings should be used. Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-45— RIGID CONDUIT Wire for two ceiling and two bracket outlets. Each ceiling outlet to be controlled by a double pole (S 1 ) flush switch. (Concealed system.) No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers . ' ■ ' ■ Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-46— RIGID CONDUIT Wire for one ceiling, one bracket, and one base receptacle outlet. Ceiling outlet to be controlled from two points using three-way snap switches. ( Exposed conduit system.) No. LIST OF MATERIALS COST Unit Total TIME REQUIRED 1 TOTAL GRADES Time Workmanship Book Record Average Copyright 1922, B. B. Burling 3mce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light ancl Power Wiring EXPOSED CONDUIT SYSTEMS In exposed conduit systems where outlet boxes are not used a fitting having separately bushed hole for each conductor must be provided. Such fittings are shown. Fig. 48. (Type A and Type C.) Openings in walls at all outlets should be closed so as to prevent electric sparks from causing fire within the partition. Ty pe T Fittin g »~v Ty pe. C Fittin g % ^ Pipe. Strops Ty pe A Fittin g with Porcelain Cover Locknut ^ | ^Bushing Fixture 5tud' Method of attachin g Conduit to Outlet boy: Fittin g with Receptacle ^Ty pe £ Fittin g Ty pe L Ffthnps used in exposed conduit work Fig. 48. Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-47— RIGID CONDUIT Wire for a series of border lights to be controlled by two single pole flush switches. Each switch to control half of the lights in such a manner that every other light will be on the same switch. (Con- cealed work.) Wiring Plan No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. , Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling' Vocational Series Light and Power Wiring National Electrical Code 1925-905-e: Must have metal of the conduit grounded as required in 905e. It is rarely possible to perfectly insulate a conduit system throughout, and a positive ground is, therefore, required, so as to first provide a definite path for leaking currents and thus prevent them from escaping through parts of a building, etc., where they may do harm. Another reason is to pre- vent any possible difference of potential occurring between conduit and near-by grounded metal work, which might cause a person to receive a dangerous shock. National Electrical Code 1925-906c: Grounding must be permanent, effective, and accessible. See Fig. 50. The ground connection should be near the point of supply so as to protect the entire conduit system. An exhaustive investigation conducted by the Bureau of Standards has shown that water pipe grounds are the most dependable. On alternating-current systems they are entirely non-injurious to the piping. Gas piping does not afford a safe means of grounding because of the increasing use of cemented joints and because of the possibility of arcing when removing sections of gas piping in which an explosive mixture of air and gas may exist.. Ground Clomp attached to Conduit Fig. 49. Fig. 50. Grounding is accomplished by means of ground clamps, Fig. 49. A ground clamp is attached to conduit system and another to water pipe. The two are connected by a copper wire of not less than No. 10 B & S gage. The wire must be soldered to the clamps and the pipes scraped bright and clean where the ground clamp is to be attached. National Electrical Code 1925-701p: Junction boxes must always be installed in such a manner as to be acces- sible. Such boxes are considered to be accessible when installed in an attic that has sufficient head room, but which is reached only by a portable ladder and permanent hatch. Copyright 1922-1926, B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Buildings made entirely of reinforced concrete present many problems to the electrical man. There are two methods by which conduit can be installed in this kind of building. °ne o^hese is to lay the conduit on the false work before the concrete is poured This is known as a slush job. The other method is to run the conduit over the rough concrete slab before the finish surface is pu on In this method it is advisable to lay out the preliminary work when the building is being erected so as to avoid drilling holes in the concrete as much as possible. The location of outlets should be provided for by placing tubes, Fig. 51, properly plugged, on the false work before the concrete is poured A good way is to fill the tubes with sand before concrete is poured. For risers a threaded piece of conduit should be set in the false work before the concrete is poured, big. Sheet Iron tube. 'Ou+lef box . Q \ -41 a * M V ■*- £> » 6 4 4 obA o. * f--*. 4 . a o '.ft 4 •* ■ • : :V ’ 4 O AO :~o "a,’ p ■ c o;o' a'.oA*': o , o ■ ■' Conduit and Qutlei box in Re-enforced Concrete. Fig. 51. Fig. 53. m Threaded pi pe. for- ris er Fig. 52. finished floor* Comute Wood floor slee per*. Ceilin g Conduit in Steef and Tile. Construction Fig. 54. When laying out a conduit installation, the size of wire necessary for the various runs should first be determined. The size of conduit to accommodate these runs should then be ascertained. T branch circuits are usually run in >4" conduit unless otherwise specified. Figs. 53 and 54 show conduit in two types of fireproof construction. The first, Fig. 53 shows where the conduit has been laid on the false work and the concrete poured around it. Tne other Fig. 54 shows where the steel and terra cotta have been put in place first and the conduit then run above same and below the finished floor. The conduit is buried in the concrete or cinder filling. Copyright 1922, B. B. Burling Bruce, Milwaukee, Publisher* Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring FLEXIBLE STEEL CONDUIT Flexible steel conduit is used for all kinds of wiring excepting concrete buildings under construc- tion. It is designed for other fireproof construction, but is equally adaptable for the wiring of fin- ished buildings. This conduit comes both in single strip, Fig. 55, and double strip type, Fig. 56. In finished buildings the double strip works better on account of its extreme flexibility. No flex- ible conduit should be imbedded in brick or run underground, or where exposed to the action of the weather. «S in g le. Stri p Double. 5tri p Fig. 55. Fig. 56. For many purposes flexible is far superior to rigid conduit. This type of conduit does not require the cutting of threads and the bending of elbows. It is easily and quickly installed. A “fish plug,” Fig. 57, will be found very useful in drawing flexible conduit in finished buildings where it is desired to fish under floors or in partitions. Connector Fig. 58. Pip e Stra p Fig. 59. Cou pling Fig. 60. After the conduit has been cut off squarely the fish plug may be screwed into the tube and the fish wire or drawing-in line attached to the eyelet on the end of the plug. The conduit must be in- stalled complete before any wires are drawn in. Connectors, Fig. 58, are used for attaching flexible steel conduit to outlet boxes. The same type of outlet boxes is used in all flexible or rigid conduit work. Where run is exposed conduit is fastened to the surface by means of pipe straps, Fig. 59. Where two pieces of flexible conduit are to be fastened together, a coupling, Fig. 60, is used. Flexible conduit must be permanently and effectually grounded the same as all other metal duct systems. The conduit must be continuous from outlet to outlet in order that wires may be readily drawn in after the system is completed. This is also to insure that the wire is protected throughout its whole length. The system should be first installed complete without conductors. The wires should not be drawn in until all mechanical work on the building has been completed as far as possible. This eliminates the danger of the wires being injured by other workmen on the job. Copyright 1922, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-48— RIGID CONDUIT Wire for one ceiling outlet controlled from three points. Three bracket outlets controlled by an electrolier (S E ) switch in such a manner that either one, two or three of the brackets may be on at one time. (Concealed work.) Wiring Plan No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers *\ c vP' Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-49— FLEXIBLE STEEL CONDlllT Wire for two ceiling and one bracket outlet. Two ceiling outlets to be controlled by No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers ' .. ( ■ . * . ■ . Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-50— FLEXIBLE STEEL CONDUIT Wire for one ceiling, one bracket and one base board outlet. Ceiling outlet to be controlled from two points, using 3 way (S 3 ) flush switches. Wiring Plan Routing Plan ******* ! \2ZZZZZZZZZ ZZZZZZZZZi XX ] CH ZZZZZZZZZZZZ ZZZZZZZZ2. No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-51— FLEXIBLE STEEL CONDUIT Wire for two ceiling, two bracket and one base outlet. Ceiling outlets to be controlled by double pole (S 2 ) flush switches and brackets by single pole (S 1 ) flush switches. Single pole switches placed below brackets. Wiring Plan No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers . . . ' Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-52— FLEXIBLE STEEL CONDUIT Wire for three ceiling outlets, controlled by an electrolier (S E ) switch, two brackets individually controlled at the fixture and a receptacle outlet controlled by a double pole (S J ) switch. Wiring Plan \ n 2-0 nun YZZ2ZZZZZZZZZZZZZZZ s £ a- ! / $ VZZZZZZZZZZZ ZZZZZZZA Routing Plan No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burlinv Vocational Series Light and Power Wiring FLEXIBLE STEEL ARMORED CABLE (BX) Flexible Steel Armored Cable consists of rubber covered wire protected from injury by two steel strips wound spirally around the conductors. Fig. 61. It is used in wiring buildings of frame construction before and after completion. In old buildings the cable is “fished” from outlet to outlet. In buildings under construction holes are bored in joists and studdings to permit the workman to draw the cable through the same way as wires are in concealed knob and tube work. It must always be looped from outlet to outlet in continuous lengths. Such cable must not be installed in basements or damp places unless additionally protected by a lead covering. Armored Conductors Fig. 61. Armored Conductor 45 o Conncctor Bushin g or Connector 90® Connector Fig. 62. Fig. 62a. National Electrical Code 1925-505c: Must be continuous from outlet to outlet or to junction boxes or cabi- nets, and the armor of the cable must properly enter and be secured to all fittings, and the entire system must be mechanically secured in position. In case of service connections and main runs, this involves running such ar- mored cable continuously into a main cut-out cabinet or gutter surrounding panel board, as the case may be. The armored cable must be run in one continuous length from outlet to outlet or outlet to junction box. Must be provided with a fitting which will securely fasten the cable to the outlet box in order to establish a good electrical contact, Figs. 62 and 62-a. Note the method of securing the connection to the armored cable. Must be equipped at every outlet with an approved outlet box or plate, as required in conduit work. In com- pleted installations the box or plate must be covered by an approved cover or fixture canopy. Outlet plates must not be used where it is practicable to install outlet boxes. For concealed work in walls and ceilings composed of plaster or wooden joists or stud construction, outlet boxes or plates and also cut-out cabinets must be so installed that the front edge will not be more than J^-inch back of finished surface of the plaster, and if this surface is broken or incomplete, it shall be repaired so that it will not show any gaps or open spaces around the edge of the outlet box or plate, or of the cut-out cabinet. On wooden walls or ceilings, outlet box or plate and cut-out cabinets must be so installed that front edge will either be flush with the finished surface or project therefrom. This will not apply to concealed work in walls or ceilings, com- posed of concrete, tile or other non-combustible material. Whenever armored cable terminates, the connector must be secured to the outlet box or plate. Fig. 63. When the installation is complete, the box or plate must be covered by an approved cover. Fig. 64e, or fixture canopy. Provide a “fixture stud” Fig. 64f at each fixture outlet where gas pipe does not provide fixture support. Method of fastenin g Flexible Steel Armored Coble to Outlet BoX. Fig. 63. ■4" Cover with 3" O p enin g Fig. 64b. Dee p Outlet Box Fig. 64c. Copyright 1922-192G. B. B. Burling Bruce. Milwaukee, Publishers Loose Leaf Shop Manual Burling' Vocational Series Light and Power Wiring All outlet boxes, Fig. 64a, c, d, plates and cabinets in concealed work must be so placed that they are not more than y back of or project more than beyond the plaster line. All openings around boxes, plates or cabinets must be closed so as to prevent a flash between conductors starting a fire in the walls. National Electrical Code: See 1925-701n. Many methods of fastening the armored cable to outlet boxes are in use. Outlet bushings or connectors are used most frequently. Fig. 63. There are also special outlet boxes which hold the cable directly to the box without the use of connectors, Fig. 64g. The connectors act as a bushing to protect the conductors from abrasion. National Electrical Code 1925-701p: Junction boxes must always be installed in such a manner as to be acces- sible. All outlet and junction boxes also fittings of similar kind shall always be installed in accessible places. Junction boxes may be considered as accessible when installed in an attic that has sufficient head room, but which is reached by a stairway or portable ladder and permanent hatch. National Electrical Code 1925-505b: For alternating-current systems must have the two or more conductors of the circuit enclosed in one metal armor. This is necessary in order to avoid heating of armor and other trouble which might occur due to induction if each conductor were separately encased. It is suggested that this be done for direct cur- rent systems, so that they may be changed to alternating current at any time. Induction troubles would prevent such a change if the wires are in separate armors. National Electrical Code 1925-505e: All bends must be so made that the armor of the cable will not be injured. The radius of the curve of the inner edge of any bend should not be less than \ l / 2 inches. The cable should not be bent too short or the sheath is liable to be opened and the conductors ex- posed and injured. Armored cable where drawn through joists should be so located that nails driven in floor will not injure it. It is best to drill the holes near the middle of the joist. When carried in slots in top of joists or in studdings as in old house wiring an iron plate should be placed over the slot before the floor is relaid or baseboards replaced. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-53— FLEXIBLE STEEL CABLE (BX) Wire for one ceiling, one bracket and one base outlet. Ceiling outlet to be controlled by single Routing Plan T 7ZZZZZZZZZZZZZZZZZZ 7Z z m > / / / » ; 7ZZZZZZZZZ 7? A , / / G 2 / ! m / I / XZZZZZZZZZZZZZZZZZZ1 \ZZZZ7ZZZZZ27ZZZZZA No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , Copyright 1922, B. B, Burling Bruce, Milwaukee, Publishers - . ■ • • • . ■ ■ ■ ' ' . •• ■ Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-54— FLEXIBLE STEEL CABLE (BX) Wire for two ceiling, one bracket and one base outlet. One ceiling outlet to be controlled by single pole (S 1 ) switch and the other by a set of three-way (S 3 ) switches. Base receptacle located directly below S\ Wiring Plan. ! a a o- 1 / / / / ZZZZZZZZZZ ZZZZZZZZZZZT VZZZZZZZZZZZZZZZsl Routing Plan. V ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZL *-0 31 s n XX xxi / / / / / / Zzzzzzzzzzzzzzzzzzzzzzzr tzzzzzzzzzzzzzzzzz No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 3922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring National Electrical Code 1 925- S05f : Must have metal armor of cables grounded with the exception of short runs of cable as permitted. The metal of all armored cable shall be permanently and effectively grounded to cold water pip- ing, but when no such piping is available, connections shall be made to gas piping on the street side of the meter. If the armored cable system consists of several separate sections, the sections shall be bonded to each other and the system grounded or each section may be separately grounded as re- quired above. When short lengths of armored cable are installed of ten feet or less in buildings of wood construction, except in basements, and where such armored cable is entirely clear of all grounded metal and installed in such a manner that there will be no possible chance of current passing through a person to ground from either armored cable or any fitting or appliance, the ground connection may be omitted. When installed in so-called fireproof buildings in course of construction or afterwards if exposed to moisture, or where it is exposed to the weather, or damp places, such as breweries, stables, etc., the cable must have a lead covering placed between the outer braid of the conductors and the steel armor. In places that are permanently damp, the armored cable shall have a lead covering over the wires and under the steel. Armored cable placed against damp masonry which will be dry when the build- ing is finished, need not have the lead covering. The lead covered cable should be used on outer walls of basements, etc., which may be permanently moist. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-55— FLEXIBLE STEEL CABLE (BX) Wire for one ceiling, two bracket and one base outlet. Ceiling outlet to be controlled from three points. Wiring Plan 3 S 2 1 TfiZZZZZZZnZZZZZZZZZZZZEZZZZZZZZZZZZZ ZZZZ/, ' n vzzzzzzzzz zzzzzzzzz S + n / / / / Routing Plan ! 3 3 1 m -0 n H- 2ZZZZZZZEZZZZZZZZZ21 l ’ZZZZZZZZZZZ ZZZZZZZ& No. LIST OF MATERIALS Unit COST Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Bruce. Milwaukee. Publishers Copyright 1922. B. B. Burling Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-56— FLEXIBLE STEEL CABLE (BX) Wire for four ceiling, two bracket, and one base outlet. Ceiling outlets each controlled by- switch. Wiring Plan Routing Plan Note. Keep this job up for jobs 56a and b. GRADES Time Workmanship Book Record Average No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL an S Copyright 1922, B. B. Burling Bruce. Milwaukee, Publishers ’ Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring FIXTURES, WIRING AND CONSTRUCTION Fixture Wire: — National Electrical Code 1925-604a: Fixtures shall be wired with approved flexible cord or approved rubber-covered wire. In wiring certain designs of show-case fixtures, ceiling bulls-eyes and similar appliances in which the wiring is exposed to temperatures in excess of 120 degrees Fahrenheit (49 degrees Centigrade), from the heat of the lamps, approved slow-burning wire should be used. All such forms of fixtures must be submitted for examination, test and approval before being introduced for use. The wire covering lies in contact with the metal of the fixtures, so that a first-class insulator, like rubber, is necessary. National Electrical Code 1925-604c: Conductors may be either solid or stranded and must not be smaller than No. 18 B and S Rage. It is very undesirable to use wires as small as No. 18 B. & S. gage, as they have but little me- chanical strength and might be broken by vibration of the fixture. They are only to be used in places where it is absolutely impossible to put a larger wire. Stranded wires are preferable to solid wires, as they are much less likely to break. In stranded conductors, each conductor must be covered with a tight close wind of fine cotton or some other method must be used to prevent a broken strand puncturing the insulation. Solid conduc- tors must be tinned. National Electrical Code 1925-1403a to h— Fixtures: Must, except in the cases mentioned in items 1-3 inclusive below, be insulated from their supports by approved insulating joints (Fig. 65c), placed as near as possible to the ceiling or walls. a. Straight electric fixtures shall be grounded except as described in 1 and 2 below. 1. Fixtures mounted on metal ceilings or side walls, or on walls or ceilings containing metal lathing, shall be grounded or shall be insulated from their supports by approved insulating joints or by approved insulating fixture supports, and canopy insulators shall be used. 2. Fixtures in open wiring, knob-and-tube work or wooden raceways and not on metal ceilings or side walls nor on plaster walls or ceilings containing metal lathing need be neither grounded nor insulated. b. Fixtures shall be considered as grounded when mechanically connected in a permanent and effective manner to metal conduit, armored cable or metal raceway systems or to a separate grounding wire not smaller than No. 14, or to gas piping which is grounded in the manner specified in article 9 of this code. (/Joint Gas Mains 6- for Conduits. Interior Conduits Sectional Vic-w Joints for Fig. 65b. Fig. 65a. Fig. 65c. Copyright 1922-1926. B. B. Burling Bruce*. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Lock Nut -s ’-Plaster ^^iSushln^ •Insulating Joint ickey Fig. 65d. When fixtures are installed out of doors they must be of watertight construction. Fig. 65d shows a method of supporting fixtures in knob and tube, armored cable and rigid conduit construction. Job L-56-a— FIXTURE WORK Assemble for inspection all fixtures complete with wire, insulating joint and hickey, Fig. 65-b for Job L-56. Secure some standard lamp cord and make the “Underwriters Knot,” Fig. 65-e. Have it inspected GRADES Time Workmanship Book Record ■. Fig. 65e. Average Job L-56-b— HANGING FIXTURES Hang all fixtures in Job L-56. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring SERVICE AND METER LOOPS (Rules governing service in most cities.) Switches and fuses shall be placed on all service wires, either overhead or underground, in the nearest accessi- ble place to the point where they enter the building, and arranged to cut off the entire current of the building, including meters. The fuses shall protect the switch, unless the knife switch is of an enclosed or protected type, under which condition the switch may be placed between the source of supply and the cut-out. On overhead service, the service entrance wires shall be brought out on that side of building nearest the poles carrying supply wires, and so installed that it shall require only one set of brackets to attach supply wires to building for connection. All overhead service wires shall enter a building through at least fa-inch rigid iron conduit, installed on the outside of the building, and shall not be less than No. 10 B and S gage. The conduit shall be equipped with a standard service head so installed that water cannot enter the fitting or conduit, (Fig. 66). The service conduit may be imbedded in brick or cement walls. The service outlet shall be so located that there will be at least 24 inches between it and any signal wires attached to the building. The service wires shall terminate on the inside of the basement wall of residences or store building entrance, and not higher than six feet from the floor within two feet of a window or door so as to make the service switch of easy access from the outside. The service wires in building, where there is no basement or in a factory building, shall terminate on the inside of the ground floor wall not higher than six feet from the floor and within two feet from a door or window, so as to make the service switch of easy access from the outside. Open service wires on outside of buildings shall be so installed so as to be at least three feet from any window, door or porch roof. Service wires shall not be smaller than No. 10 B and S gage and in overhead service the street ends shall extend at least 24 inches from service head. Service wires shall not be attached to any roof, or along any building wall, unless installed in standard rigid conduit. Service conduit shall be used solely for service wires. In overhead service the service conduit on a one story building shall run up to the highest available point on that side of the building where the service wires are to be connected, and on all other buildings to a point not less than fifteen feet from the ground. When more than one service enters a building, the distance of points of entrance of the different service wires shall not be more than twenty-four inches. Any underground service from a subway to a building shall not supply more than one building unless the conductors are carried outside all the buildings but the ones served. Conductors buried under two inches of con- crete under a building or buried back of two inches of concrete or brick within an outside wall are considered as lying outside of the building. These requirements do not apply to factory yards or factory buildings under single occupancy or management. On underground service the service wires shall enter so that the service switch, which is to be placed as near as possible to the place where the service wires enter, shall be located near a window or entrance door, so as to make the service of easy access from the outside. Where there are more than two meters in an installation, each meter shall be protected by a separate cut-out. All meter loops shall not be smaller than No. 10 B. & S. gage wire and shall be run in conduit with standard meter outlet fittings at each meter, except where meter cabinets are used, or where the meter loops are larger than No. 2 B. & S. gage in which case a standard conduit fitting may be used. All switches in distribution cabinets and meter loops shall be labeled and numbered for identifica- tion and meter loops brought out in consecutive order. Meter boards shall be at least three-fourths of an inch in thickness and made so as to prevent warping and treated with shellac, insulating paint or varnish. Meters shall not be installed in bathrooms, bedrooms, clothes closets, sitting rooms, stairways, attics, coal bins or inaccessible places. If several meters are to be installed in one place, sufficient room shall be allowed to permit good mechanical and electrical construction. If meters and service switches are exposed to mechanical injury or dust, such as in flour mills, saw mills, etc., they shall be protected by a suitable cabinet. The general arrangements of meter loops should be such that a meter can be installed without crossing any wires. Meter loops should not be placed above 7 feet from the floor, and should be as near the point of entrance of the service as possible. In office buildings meter loops should be located at a central point in meter closets or public corridors, and in apartment buildings in the basement of the building, so that meters may be installed and maintained without annoyance to tenants. At the meter outlet there should be provided either a meter terminal fitting, Fig. 67, or multiplex box, Fig. 68. Sufficient length of wire should be left when multiplex boxes are used to connect up meter in such a manner that there will be no crossing of wires and that there will be good mechanical and elec- trical construction. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring r Me-ter Board.--'* Me-fcer — Multiplex Dox- To , _ Distribution. Cabin© r =n= Lu,J Service Wires Service Head (To be located u-t lea sl 15' from the ground and 3' from a. iv in dour) -L Conduit Fitting Fig. 66. Fig. 67. Fig. 68. Before installing meter terminal fittings or multiplex, the local lighting and power company should be consulted to ascertain the type of meter they intend installing so that the proper meter loops can be provided. There are a number of different types of meters on the market, each requiring a different arrangement of meter loops. Figure 69 shows the connections for a number of types. Connections for 2 Wire Single Phase Meter .^Current Coil Connection fur 2 Wire Single Phase Meter Connections for 3 Wire Sin gl e Phase Meter El/lfae 4 Binding Post T ype Direct Current Meter une 3Wire 4 Bindin g Post T ipc D irect Current Meter Connections for Three Phase 220 Volt Meter Fig. 69. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-57— METER LOOPS Wire for meters of a four family apartment using meter terminal fittings, Fig. 67. Each apart- ment to have two circuits. Each meter to be fused separately. Three wire service. |QOOOO|f P* jooooo) ] It loop oo| toooool No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers ' * • ■ ■| • . * Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-58— METER LOOPS Wire for a two wire service to a single customer. Wire so that all wires to meter and building are dead when the service switch is open. Use a two wire meter. Copyright 1922, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record . Average. . . Copyright 1922-lfi2U. I!. Ii. Hurling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-59— METER LOOPS Wire for three wire service to two customers. Run three wires to each meter. Copyright 1922, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring No. COST LIST OF MATERIALS Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . Copyright 1922. B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L- 60 — METER LOOPS Wire for a three wire service to a single customer. Three wire meter. 0 // L V X W — \N I' ll H ) /a s '\ s/' I Leave of wire for each meter loo p. O peratin g handliA interchan g eable.. To be placed on side nearest window. o s O CVJ Qj <3 CD £ O C cO CD 1_ C5 CD C CD "O V> c o T3 CD CD CT> <3 cD -Q a CD cr C3 o D. CD <: a) ST <3 CD Q_ CD -Q —iO oil— Copyright 1922, B. B. Burling Bruce. Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record . Average. . . Copyright 1922, B. B. Burling Bruce. Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-66— METER LOOPS Wire for a three-wire service to a single customer using a Square D switch, compensator type, as a service and meter switch. Use two-wire meter. ‘List of Materials” on other side. Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record , Average. . . Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Job L-67— METER LOOPS Wire for a three phase service to a single customer using a three phase 220 volt meter. ‘List of Materials” on other side. Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record , Average. . . Copyright 1922. B. B. Burling Bruce. Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Figure 71 shows a typical installation of meters for a large apartment building using two and three wire meters and having the customer’s distribution cabinet located in basement with meters. s? 3 a 56 10 75 m 94- 15 113 Copyright 1922-192(1. B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record Average. . , MOTORS D. C. AND A. C. National Electrical Code 1925-1001a: Must when operating at more than 150 volts potential and accessible to other than qualified attendants have their frames grounded. When frames are not grounded and the voltage of the circuit exceeds 150 volts to ground, the frames shall be permanently and effectively insulated from ground. The reason for requiring a positive ground is to prevent a possible difference of potential existing between motor frame and nearby grounded objects, in the event of breakdown of motor insulation, which might cause a person making contact between the two to receive a dangerous shock. National Electrical Code 1925-1003g and h: Each motor must be controlled by an indicating switch which will disconnect all ungrounded leads when opened. A single pole switch must not be used on motors of over horse- power. Automatic starting, except auto-transformer, switches may be used without other main control switch. To comply with the above rule in the case of a squirrel cage or similar type motor having a large starting current it will be necessary to use a motor starter or double throw switch so designed that the protective device will be shunted or cut out of service during the starting period unless a time limit circuit breaker or similar device is used which will prevent the opening of the circuit during the starting period. Copyright 1922-1926, B. B. Burlini Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring JOB L-69 — A. C. MOTOR INSTALLATION Wire for three horse power, three phase motor, using safety starting switch. Enclose all wires in conduit. Show complete wiring diagram. H.P. Motor 220V Size Wire Size Conduit Amperes of Starting Fuses Amperes of Running Fuses Size of Switch Name Plate Amperes i 3 10 6 30A 2 6 13 10 30A 3 4 20 15 30A 5 15 30 20 30A 7* 21 40 30 60A 10 28 60 40 60A IS 42 80 60 1O0A 20 52 100 75 lOOA Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring No. LIST OF MATERIALS COST Unit Total TIME REQUIRED TOTAL GRADES Time Workmanship Book Record , Average. . . Conductors carrying the current of only one motor must have a carrying capacity of at least 110 per cent of the name plate current rating of the motor. To provide for the large starting current of certain types of A. C. motors without overfusing the conductors, wires considerably larger than 110 per cent of motor name plate rating may be neces- sary in that part of the circuit not included in the protection afforded by the motor protective device. All wiring to motors from cutout cabinets, circuit breakers or switches should be in rigid con- duit. At the motors the conduit should be provided with a suitable fitting with bushed openings or porcelain cover. Although the code does not demand, it is best to have the starting switch one of the enclosed safety type. There are many of these on the market. Fig. 73 shows one type of safety start- ing switch. Copyright 1922-1926, B. B. Burling Bruce, Milwaukee. Publishers Loose Leal Shop Manual Burling Vocational Series Light and Power Wiring TYPICAL FLOOR PLANS The floor plans on the subsequent sheets may be used as problems in contracting and estimating or merely as illustrative of commerqial practice. Should a course in “Contracting and Estimating” be planned to follow this course on “Light and Power Wiring” plans suitable for the same can be obtained from the publisher. F'ifc’st Floor Flan Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Table Lomp,Vac.flwner or Fan Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring Second "Floor Flan Copyright 1922, B. B. Burling Bruce, Milwaukee, Publisher! Cellar Plan Copyright 1922, B. B. Burling Bruce, Milwaukee, Publishers Loose Leaf Shop Manual Burling Vocational Series Light and Power Wiring RESUSCITATION FROM ELECTRIC SHOCK Rules Reeommendcd by Commission on Resuscitation from Electric Copyrighted 1 912. ,o by E>«,°” Sf F° LLOW THESE instructions even if victim appears dead I. Immediately break the circuit. With a single quick motion, free the victim from the current ttv„ . board) to move either the victim or the wire. Beware of usfns m s n ne?k, ^ ^“kor'wais’”' 1 WhU,! “ ‘ S co “' in “< i ' an assistant should breathing is restored, o^unUlTphyskLii' artraf^’lf Suraf'bMathiig” rtoo Wi f', h °“! i ' n,err “P' ion ' “"til natural respiration again. natural breathing stops after being restored, use artificial 3. Do not give any liquid by mouth until the subject is fully conscious. Give the subject fresh air, but keep him warm III. Send for nearest doctor as soon as accident is discovered. Copyright 1922. B. B, Burling Bruce, Milwaukee. Publishers Loose Leaf Shop Manual Barline Vocational Series Light and Power Wiring USEFUL DATA CONDUIT SIZES FOR DIFFERENT SIZE WIRES No. Circular Amperes Size of Pipe - Circular Amperes r Size of Pipe - B. & S. Mills Rubber 1 Wire 2 Wire 3 Wire Mills Rubber 1 Wire 2 Wire 3 Wire 18 1,020 3 % % % 600,000 390 1% 3 3 16 2,683 6 % % % 550,000 420 1% 3 2% 14 4,107 12 % % % 600,000 460 2 3 3% 12 6,630 17 % % % 660,000 475 2 3% 3% 10 10,380 24 % % % 700,000 600 2 3% 3% 8 16,610 33 % % 1 760,000 625 ' 2 3% 3% 6 26,260 46 % 1 1% 800,000 550 2 3% 4 6 33,100 54 % 1% 1% 860,000 676 2 3% 4 4 41,740 66 % 1% 1% 900,000 600 2 3% 4 3 62,630 76 % 1% l Vi 950,000 625 2 4 4 2 66,370 90 % 1% 1% 1,000,000 650 2 4 4 1 83,690 107 % 1% 1% 1,100,000 690 2% 4 4% 0 105,600 127 1 1% 2 1,200,000 730 2Vi 4% 4% 2.0 133,100 160 1 2 2 1,300,000 770 2% 4% 5 3.0 167,800 177 1 2 2 1,400,000 810 2% 4y 2 6 4.0 211,600 210 1% 2 2% 1,600,000 850 2% 4% 5 200,000 200 1% 2 2% 1,600,000 890 2% 5 6 260,000 235 1% 2% 2% 1,700,000 930 3 6 5 300,000 270 1% 2% 3 1,800,000 970 3 6 6 350,000 300 1% 2% 3 1,900,000 1,010 3 6 6 400,000 330 1% 3 3 2,000,000 1,050 3 6 6 • • 460,000 380 1% 3 3 . . . ... ... Allowances have been made in the table for the easy pulling of wires around three elbows, so that in straight, snort runs, conduit a size smaller may be used, excepting that J^-inch is the smallest size permitted by the under- writers’ rules. In laying out a conduit job, first ascertain the size and number of wires required, then take the sizes of conduit from the above table. One-half inch is usually used for branch conduits and is the smallest size permitted by the National Electric Code. In running several conduits together, a pull box will be found more economical than elbows for making turns, as one pull box will take the place of several elbows. Do not pull wires through conduits with a block and tackle, as it will not only injure the insulation, but wedge the wires in such shape that they cannot be removed readily if desired. Be careful to ream out the end when conduit is cut, as the burr may otherwise cut through the insulation. Conduits should be securely fastened to walls and ceiling by use of pipe straps or hooks. Plug all exposed ends of conduit in new buildings to prevent plaster and dirt from falling into it. DIMENSIONS, RESISTANCES AND SAFE CARRYING CAPACITY OF COPPER WIRES B. AS. Diameter in Mils. Area in Ohms Safe Amperes Gauge or Thousandths Circular Per Rubber Weather- No. of an Inch Mils. 1,000 Ft. Covered proof 1,000 1,000,000 .01038 660 1,000 894 800,000 .01297 550 840 775 600,000 .0173 450 680 707 500,000 .02076 400 600 632 400,000 .02596 326 600 548 300,000 .0346 275 400 0000 460 211,600 .04906 225 325 000 410 167,805 .06186 175 276 00 365 133,079 .07801 150 225 0 325 105,592 .0983 126 200 1 289 83,694 .1240 100 160 2 258 66,373 .1564 90 126 3 229 52,633 .1972 80 100 4 204 41,742 .2487 70 90 6 182 33,102 .3136 55 80 6 162 26,260 .3965 50 70 8 128 16,609 .6288 36 60 10 102 10,381 1 . 26 30 12 81 6,630 1.690 20 25 14 4,107 2.691 15 20 16 61 2,683 4.019 6 10 18 40 1,624 6.391 3 5 Copyright 1922. B. B. Burling .Bruco, Milwaukee. Publishers I I ( <<