f. Must be separated from contact with walls, floors, timbers, or partitions through which they may pass by non-combustible insulating tube or hard-rubber tube.

g. Must be so spliced or joined as to be both mechanically and electrically secure without solder. They must then be soldered to insure preservation, and covered with an insulation equal to that on the conductors.

13. ARC LAMPS-in every case

a. Must be carefully isolated from inflammable material.

b. Must be provided at all times with a glass globe surrounding the arc, securely. fastened upon a closed base. No broken or cracked globes to be used.

c. Must be provided with an approved hand switch, also an automatic switch, that will shunt the current around the carbons should they fail to feed properly.

d. Must be provided with reliable stops to prevent carbons from falling out in case the clamps become loose.

e. Must be carefully insulated from the circuit in all their exposed parts.

f. Must be provided with a wire netting around the globe and an approved spark · arrester above to prevent escape of sparks, melted copper or carbon, where readily

inflammable material is in the vicinity of the lamps. It is recommended that plain carbons, not copper-plated, be used for lamps in such places.

g. Hanger-boards must be so constructed that all wires and current-carrying devices thereon shall be exposed to view, and thoroughly insulated by being mounted on a water-proof, non-combustible substance. All switches attached to the same must be so constructed that they shall be automatic in their action, not stopping between points when started, and preventing an arc between points under all circumstances. 14. INCANDESCENT LAMPS IN SERIES CIRCUITS HAVING A MAXIMUM POTENTIAL OF 300 VOLTS OR OVER

a. Must be governed by the same rules as for arc lights, and each series lamp provided with an approved hand-spring switch and automatic cut-out.

b. Must have each lamp suspended from a hanger-board by means of a rigid tube.

c. No electro-magnetic device for switches and no system of multiple-series or series-multiple lighting will be approved.

d. Under no circumstances can series lamps be attached to gas fixtures.

CLASS C.

INCANDESCENT (LOW-PRESSURE) SYSTEMS.

300 VOLTS OR LESS.

15. OUTSIDE OVERHEAD CONDUCTORSa. Must be erected in accordance with the rules for arc (series) circuit conductors.

b. Must be separated not less than 12 inches, and be provided with an approved fusible cut-out that will cut off the entire current as near as possible to the entrance to the building and inside the walls. 16. UNDERGROUND CONDUCTORS—

a. Must be protected against moisture and mechanical injury, and be removed at least two feet from combustible material when brought into a building but not connected with the interior conductors.

b. Must have a switch and a cut-out for each wire between the underground conductors and the interior wiring when the two parts of the wiring are connected.

These switches and fuses must be placed as near as possible to the end of the underground conduit and connected therewith by specially insulated conductors, kept apart not less than two and a half inches.

c. Must not be so arranged as to shunt the current through a building around any catch-box.

INSIDE WIRING-GENERAL RULES.

17. At the entrance of every building there shall be an approved switch placed in the service conductors by which the current may be entirely cut off.

18. CONDUCTORS

a. Must have an approved insulating covering, and must not be of sizes smaller than No. 14 B. & S., No. 16 B. W. G., or No. 4 E. S. G., except that, in conduit installed under Rule 22, No. 16 B. & S., No. 18 B. W. G., or No. 4 E. S. G. may be used.

b. Must be protected when passing through FLOORS, or through walls, partitions, timbers, etc., in places liable to be exposed to dampness by waterproof, noncombustible, insulating tubes, such as glass or porcelain.

Must be protected when passing through walls, partitions, timbers, etc., in places not liable to be exposed to dampness by approved insulating bushings specially made for the purpose.

c. Must be kept free from contact with gas, water, or other metallic piping, or any other conductors or conducting material which they may cross (except high potential conductors) by some continuous and firmly fixed non-conductor creating a

separation of at least one inch.

Devia

tions from this rule may sometimes be allowed by special permission.

NIA

d. Must be so placed in crossing high potential conductors that there shall be a space of at least one foot at all points between the high and low tension conduc

tors.

e. Must be so placed in wet places that an air-space will be left between conductors and pipes in crossing, and the former must be run in such a way that they cannot come in contact with the pipe accidentally. Wires should be run over all pipes upon which condensed moisture is likely to gather, or which by leaking might cause trouble on a circuit.

INSIDE WIRING-SPECIAL RULES.

19. WIRING NOT ENCASED IN MOULDING OR APPROVED CONDUIT

a. Must be supported wholly on noncombustible insulators, constructed so as to prevent the insulating coverings of the wire from coming in contact with other substances than the insulating supports.

b. Must be so arranged that wires of opposite polarity, with a difference of potential of 150 volts or less, will be kept apart at least two and one half inches.

c. Must have the above distance in