Electric light wiring

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McGraw Publishing Company, 1907 - Architecture - 219 pages

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Page 63 - Centigrade) they will carry indefinitely a current 10 per cent, greater than that at which they are rated, and at a current 25 per cent, greater than the rating, they will open the circuit without reaching a temperature which will injure the fuse tube or terminals of the fuse block. With a current 50 per cent, greater than...
Page 175 - Must be so spliced or joined as to be both mechanically and electrically secure without solder. The joints must then be soldered to insure preservation and covered with an insulation equal to that on the conductors.
Page 59 - Fuses should be stamped with about 80 per cent of the maximum current they can carry indefinitely, thus allowing about 25 per cent overload before the fuse melts. With naked open fuses of ordinary shapes and not over 500 amperes capacity, the maximum current which will melt them in...
Page 99 - The wiring in any building must test free from grounds; ie, the complete installation must have an insulation between conductors and between all conductors and the ground (not including attachments, sockets, receptacles, etc.) not less than that given in the following table...
Page 15 - All elbows or bends must be so made that the conduit or lining of same will not be injured. The radius of the curve of the inner edge of any elbow not to be less than three and one-half inches.
Page 15 - The object of a tube or conduit is to facilitate the insertion or extraction of the conductors to protect them from mechanical injury and, as far as possible, from moisture. Tubes or conduits are to be considered merely as raceways, and are not to be relied upon for insulation between wire and wire, or between the wire and the ground.
Page 177 - The ground connection for central stations, transformer substations, and banks of transformers should be made through metal plates buried in coke below permanent moisture level, and connection should also be made to all available underground piping systems, including the lead sheath of underground cables. For individual transformers and building services the ground connection may be made to...
Page 16 - Department having jurisdiction, provided that the conduit ends are bushed and secured. e. Metal conduits, where they enter junctio'n boxes and at all other outlets, etc., must be provided with approved bushings fitted so as to protect...
Page 18 - Must not be drawn in until all mechanical work on the building has been, as far as possible, completed. p. Must, for alternating systems, have the two or more wires of a circuit drawn in the same conduit. It is advised that this be done for direct-current systems also, so that they may be changed to alternating systems at any time, induction troubles preventing such a change unless this construction is followed. For concealed ' ' knob and tube '
Page 43 - The lower limit is specified for rubber-covered wires to prevent gradual deterioration of the high insulations by the heat of the wires, but not from fear of igniting the insulation. The question of drop is not taken into consideration in the above tables.

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