WIRES ENTERING BUILDINGS.

II. Whenever electric light wires enter buildings through their exterior walls the wires must be firmly supported and incased in tubes of non-conducting material not liable to absorb moisture (e. g. porcelain or glass) and so placed as to prevent the entrance of rain water along the wires (e. g. the tubes must slope upward as they pass inward through the wall).

12. Both the ingoing and return wires should enter the building at the same location and pass through an approved manuel "cut-out-box" or switch, which must be placed where it will be easy of access to firemen and the police.

HIGH POTENTIAL WIRES WITHIN BUILDINGS.

13. In the interior of buildings wires for arc lights besides being covered with an insulating covering such as has already been described must be in all cases securely attached and supported by insulators which shall keep them out of contact with any wall, partition, ceiling or floor, so as to secure an air space of at least one-quarter inch between the wire and any adjacent wall, partition or floor, and whenever the wires cross or come near to any other wires, pipes or other conductors, the wires must all be rigidly secured and separated from each other or any other conductors by means of some rigid non-conducting material.

14. Arc wires of opposite polarities (i. e., the incoming and outgoing wires from each lamp or of each circuit) must be kept at a distance not less than eight inches from each other except within the structure of lamps or on switch boards, cut-out boxes or the like where a nearer approach is necessary.

15. In exceptional cases, however, where the wires are so rigidiy secured and insulated that contact or connection between them is quite impossible they may be allowed to approach nearer. (e. g. If each wire or conductor is covered with a thick and undisplacable insulation which in turn is covered by a leaden sheath or pipe, and then two or more such pipes are inclosed in an iron pipe in such manner that injury to the lead covered cables is impossi

ble, this would be an allowable substitute for the eight inches of absolute separation called for in the general rule.)

16. Whenever wires are carried through walls, partitions or floors within a building, they must be surrounded by a special rigid insulating tube or casing impervious to water, and must be so attached and supported as to be secure from abrasion or other mechanical injury.

NOTE.-Rubber tubing will not meet the above requirements as an insulation.

ARC LAMPS.

17. The exterior frames and other exposed parts of arc lamps must be securely insulated from the electric circuit, and all such lamps must have glass globes surrounding the light and inclosed below, so as to prevent the fall of ignited particles. Where inflammable materials are placed below such lamps the globe must be surrounded by a wire netting capable of keeping the parts of the globe in place if it is fractured in use.

NOTE.-Broken globes must be replaced as soon as practicable by new ones.

18. In show windows and other places where inflammable materials are displayed, and in factories or wood-working establishments where "flyings" may be present in the air, each lamp must be provided with "spark arresters."

19. Each lamp must be provided with a hand-switch and also with an automatic switch which shall shunt the current round the carbons before the arc between them reaches a dangerous length.

LOW POTENTIAL SYSTEMS.

DIRECT SYSTEMS.

20. In direct incandescent systems, the rules as to the capacity, location and arrangement of conductors is substantially the same as has been already stated, with the following exceptions:

21. In case the difference of potential at the positive and negative posts of the dynamo or dynamos developing the current is not more than 250 volts the positive and negative wires in aerial lines and elsewhere which would otherwise be required to maintain a minimum distance of ten inches, may be brought to within six inches of each other. Also underground conductors may be enclosed both in the same tube, and if rigidly and securely supported, and surrounded by and imbedded in a solid insulating substance, may lie within one-quarter inch of each

other.

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22. When underground service conductors enter building care must be taken that they are at once separated to the required distance (see below) and are adequately and permanently insulated from each other and from the pipe in which they were inclosed, if they were inclosed in a metallic pipe or conduit.

23. They must also be adequately protected from mechanical injury and must be so located that a cut-out can be safely and conveniently located close to the end of the service pipe or conduit by which they are brought in.

LOW POTENTIAL WIRES WITHIN BUILDINGS.

24. In the distribution of the conductors through buildings "concealed work," such as the placing of wires under floors or within partitions, walls or ceilings should be avoided as much as possible.

25. In perfectly and securely dry localities an improved insulated wire without waterproof covering may be used, provided the wires are not concealed and are supported by cleats or insulators.

26. Wherever the wires are to be in any way covered up they must be coated with an approved waterproof insulation.

27. In all cases of concealed work, the company proposing to introduce the same, will be required to furnish the Board with a detailed diagram of the work, showing the kind and size of wire used at the different branches, with particulars as to the insulation and in what materials embedded; location of cut-outs, switches, etc. The dia

gram to be signed and sworn to by an officer of the company and filed with the Board for reference.

28. If wires are embedded in the plaster or walls, ceiling or partitions, they must be separated not less than ten inches from each other, in addition to being insulated as above described.

29. In buildings in course of construction, terminal wires must be so arranged as to be secure from injury by the plasterers.

30. Wires insulated as above may be covered by or embedded in mouldings in dry locations, but in breweries, paper mills, dry houses, and other like places where they are exposed to moisture, they must be carried out of contact with the walls, ceilings and the like on approved "insulators."

SECONDARY SYSTEMS.

31. In these systems where alternating currents of high electro-motive force are used on the main lines, and secondary currents of low electro-motive force are developed in local "converters" or "transformers," it is important that the entire primary circuit and the transformers should be excluded from any insured building, and be confined to the aerial line (the transformers being attached to the poles or the exterior of the buildings) or to underground conduits if such are used, or placed in fire-proof vaults or exterior buildings.

32. In those cases, however, where it may not be possible to exclude the transformers and entire primary from the building, the following precautions must be strictly observed:

33. The transformer must be constructed with or inclosed in a fireproof or incombustible case, and located at a point as near as possible to that at which the primary wires enter the building. Between these points the conductors must be heavily insulated with a coating of approved waterproof material, and, in addition, must be so covered-in and protected, that mechanical injury to them, or contact with them, shall be practically impossible.

34. These primary conductors, if within a building,

must also be furnished with a double-pole switch, or separate switches on the ingoing and return wires and also with automatic double pole cut-out where they enter the building or where they leave the main line, on the pole or in the conduit. The switches above referred to should, if possible, be inclosed in secure and fireproof boxes outside the building.

35. In the case of isolated plants using the secondary system, the transformers must be placed as near to the dynamos as possible, and all primary wires must be protected in the same manner as is indicated in the second paragraph above.

INSULATION.

36. Where there is a possible exposure to water, the first or second coating must be impervious to the fluid.

37. For incandescent lamp fixtures and electroliers, exceptions may be made to the foregoing rule in which the wires can be placed nearer than the prescribed distance to each other, or to other conductors, provided the fixture is fully insulated at the base from house and ground piping, and further provided that a double pole safety catch is placed at the base of each fixture, or at the nearest branch connection as may be required by the Inspector of the Board.

38. In all cases when combination (gas and electric) fixtures are used, extra precaution must be used to secure complete and continuous insulation from the gas piping.

INSULATION IN GENERAL.

39. It is to be understood as a general or universal rule that all machines, lamps, wires and other parts of electric systems, are to be so constructed, mounted and secured as to insure complete and continuous insulation; with such exceptions only as are herein before stated, and that in no case shall ground circuits be employed or any part of the system be allowed to come in contact with the earth through gas or water pipes or the like.