Fig. 869.—Standard wooden moulding for encasing wires. Wooden moulding must not be used in concealed or damp places, nor be placed directly against a brick wall where sweating may introduce moisture that may ultimately cause a short circuit. Wooden moulding for concealing electrical conductors is prohibited by ordinances in some cities.
Ques. For what conditions is wiring in mouldings suitable?
Ans. It is adapted to installations in which the wires have to be laid after the completion of the buildings.
Ques. Describe the moulding usually employed.
Ans. It is made of hardwood in two pieces, a backing and cap, so constructed as to thoroughly encase the wire.
It should provide a one-half inch tongue between the conductors and a solid backing which should not be less than three-eighths of an inch in thickness under the grooves; it should be able to give suitable protection from abrasion.
The inside of the moulding and the cap must have at least two coats of waterproof material, or else the whole moulding must be impregnated with moisture repellant.
Only one conductor is placed in a groove.
The backing is secured to the walls or ceilings by means of wire nails. The wires are then laid in the grooves and the capping put in place and fastened by small brads.
The wires should be continuous, and only rubber covered wire should be employed.
Wooden moulding is made in a great variety of size and design. The general appearance of this type of moulding being shown in [fig. 869].
Ques. What other kind of moulding is used?
