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singly on separate timbers or studding. (f) When thus run in perfectly dry places not liable to be exposed to moisture, a wire having simply a non-combustible insulation may be used.

33. Wires run as above (a) immediately under roofs, (b) in proximity to water tanks, or pipes, will be considered as exposed to moisture; and in such places the insulating covering of the wire must consist of a waterproof covering next the wire, protected by an external covering not easily abraded, and that will not support combustion.

34. Wires must not be fished (a) for any great distance, and (b) only in places where the inspector can satisfy himself that the above rules have been complied with. (e) Twin wires must never be employed in this class of concealed work.

Conduit Wiring.

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35. Wires may also be concealed by means of a system of insulating tubes, or "conduits,' that are moisture-proof and practically noninflammable, and have a threaded joint. (a) A separate tube must be provided for each wire, except (b) in case of taps or branches carrying a current that does not exceed fifteen ampères, in which case a flexible twin cable. may be used; but (c) the two conductors of this cable must not be insulated from each other by a rubber compound. A cotton or other fibrous covering should be used, and (d)

the joints between sections must be made moisture proof, with some cement proper for the purpose; i. e.. the whole system must be free from joints, cracks, etc., where it would be possible for moisture to enter the tubing.

36. These tubes may be secured by metallic loops, and may be laid side by side.

37. This is the only manner in which wires may be run imbedded in plaster, cement, or any similar material. Wires run on brick walls or below timbers furred for lath and plaster will be considered as imbedded in plaster, unless the furring strips are of such thickness as to prevent any contact between the wire and the clinches of plaster.

Wires in Damp Places.

38. In dye-houses, paper and pulp mills, and other buildings especially liable to moisture, all wires, except those used for pendants, must (a) be separated at least six inches, (b) be thoroughly and carefully put up, and (c) be supported by glass or porcelain insulators, or by rubber hooks.

39. Where it is necessary to run the wires down a side wall in order to pass through a floor, the wires must (a) be supported from the ceiling to the floor on insulators, (b) placed, if necessary, on a back-board, and (c) to protect the wires from injury, they should be boxed over from the floor to a point five or six feet above.

40. Where exposed to acid fumes, vapors of ammonia, etc., wires should (a) be provided with an insulation, and (b) supported on insulators that will not be injured thereby.

41. In places covered by Rules 38 and 40 wires may be run under rules for "conduit" wiring, and if to be concealed they must be so run, but in either case will be subject to special approval by the inspector.

FITTINGS AND APPARATUS.

Safety Cut-Outs.

42. (a) Every portion of each installation must be equipped with safety cut-outs, that will interrupt the passage of a current in excess of the amount which that portion of the apparatus is adequate to transmit. (b) Fusible leads designed to carry a current of ten ampères or over must have contact surface of some harder metal. (c) Fusible leads should be proportioned to the capacity of the wire they are to protect, and not to the number of ampères required to supply the lamps on that particular circuit. (d) A cut-out must be placed where the underground or overhead service joins the inside wires, and (e) at every point where a change is made in the size of the wire (unless the cut-out in the larger wire is intended to protect the smaller). (ƒ) A cut-out must be provided for each fixture, and (g) in concealed wiring, for each pendant also; but (h) where the wires are exposed, one cut

out may be employed to protect two or more pendants, provided (i) the amount of current they require does not exceed seven ampères. (j) Stiff brackets not attached to gas pipes may be treated as pendants in this connection.

43. All cut-out devices must (a) be made of non-combustible material, (b) be placed so as to protect both sides of the circuit, and (c) be provided with close-fitting covers.

44. When lights are grouped, as upon electroliers, etc., the small wires to each light cannot always have cut-outs. Care should be taken, however, that the last controlling cutout (a) carries as small an amount as practicable, and (b) that it will act before the smallest wire runs any risk of being unduly heated. Switches.

45. All switches must (a) be composed entirely of non-combustible material, and (b) be automatic in action.

46. All switches must be double-pole, in circuits (a) connected to fixtures attached to gas pipes, or (b) carrying a current of ten ampères or over.

Pendants, Portables, Etc.

47. (a) Lamps may be suspended by flexible cord pendants not less than No. 16 B. & S. or No. 18 B. W. G. (b) Where it enters the lamp socket, the cord must be protected by a bushing of rubber, wood, or some similar

insulating material, and (c) the cord must be so arranged that the weight of the lamp, etc., shall not be borne by the joints or binding screws.

48. (a) The covering of the flexible cord, as a whole, shall be of such a nature that it will not support combustion, (b) in damp places the cord must have a moisture-proof covering, and (c) the opening at the top of the socket must be closed, so as to prevent the entrance of water. (d) The flexible leads of portable fittings must in all cases be protected by cutouts at their fixed points of connection.

Fixtures.

49. (a) Each fixture to which wires are attached must be insulated from the piping of the building by an insulating joint. (b) Burrs and sharp edges must be removed before wires are drawn into a fixture. (c) Wires attached to or concealed within fixtures must have an insulating covering that cannot be easily cut or abraded, and (d) that is moisture proof; (e) where attached to the outside of a gas fixture, the conductors must be so secured that their covering will not be cut or abraded by the swaying of the fixture or the movement of the bracket arm. (f) The difference of potential between any two wires connected with a combination or gas fixture must not exceed 125 volts. (g) No wire smaller than No. 16 B. & S. or No. 18 B. W. G. must be used in fixture wiring.

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