f. 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. (See Definitions).

SPECIAL RULES.

19. WIRING NOT ENCASED IN MOLDING 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 increased proportionately where a higher voltage is used.

d. Must not be laid in plaster, cement or similar finish.

e. Must

staples.

never be fastened with

IN UNFINISHED LOFTS, BETWEEN FLOORS AND CEILINGS, IN PARTITIONS, AND OTHER CONCEALED PLACES.

f. Must have at least one inch clear air space surrounding them.

g. Must be at least ten inches apart when possible, and should be run singly on separate timbers or studding.

h. Wires run as above immediately under roofs, in proximity to water tanks or pipes, will be considered as exposed to moisture.

i. When from the nature of the case it is impossible to place concealed wire on non-combustible insulating supports of glass or porcelain, the wires may be fished on the loop system, if encased throughout in approved continuous flexible tubing or conduit.

j. Wires must not be fished for any great distance, and only in places where the inspector can satisfy himself that the above rules have been complied with.

k. Twin wires must never be employed in this class of concealed work.

20. MOLDINGS:

a. Must never be used in concealed work or in damp places.

b. Must have at least two coats of waterproof paint or be impregnated with a moisture repellant.

c. Must be made of two pieces, a backing and capping, so constructed as to thoroughly encase the wire, and maintain a distance of one-half inch between conductors of opposite polarity, and afford suitable protection from abrasion. 21. SPECIAL WIRING:

In breweries, packing houses, stables, dye-houses, paper and pulp mills, or other buildings specially liable to moisture or acid, or other fumes liable to injure the wires or insulation, except where used for pendants, conductors

a. Must be separated at least six inches.

b. Must be provided with an approved waterproof covering. (See Definitions). c. Must be carefully put up.

d. Must be supported by glass or por

celain insulators. No switches or fusible cut-outs will be allowed where exposed to inflammable gases or dust, or to flyings of combustible material.

e. Must be protected when passing through floors, walls, partitions, timbers, etc., by waterproof, non-combustible, insulating tubes, such as glass or porcelain. 22. INTERIOR CONDUITS*:-(See Definitions).

a. Must be continuous from one junction box to another, or to fixtures, and must be of material that will resist the fusion of the wire or wires they contain without igniting the conduit.

b. Must not be of such material or construction that the insulation of the conductor will ultimately be injured or destroyed by the elements of the composition.

*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 on for insulation between wire and wire, or between the wire and the ground.

c. Must be first installed as a complete conduit system, without conductors, strings, or anything for the purpose of drawing in the conductors, and the conductors then to be pushed or fished in. The conductors must not be placed in position until all mechanical work on the building has been, as far as possible, completed.

d. Must not be so placed as to to be subject to mechanical injury by saws, chisels, or nails.

e. Must not be supplied with a twin conductor, or two separate conductors, in a single tube. (See page 198, Rule 22).

f. Must have all ends closed with good adhesive material, either at junction boxes or elsewhere, whether such ends are concealed or exposed. Joints must be made air-tight and moisture proof.

g. Conduits must extend at least one inch beyond the finished surface of walls or ceilings until the mortar or other similar material be entirely dry, when the projection may be reduced to half an inch.