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Cut-Out Panels Outlet-Boxes

outlet-box, conduits, conduit, outlet, require, fig and floor

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OUTLET-BOXES, CUT-OUT PANELS, AND OTHER ACCESSORIES Outlet-Boxes. Before the introduction of iron conduits, outlet boxes were considered unnecessary, and with a few exceptions were not used, the conduits being brought to the outlet and cut off after the walls and ceilings were plastered. With the introduction of iron con duits, however, the necessity for outlet-boxes was realized; and the Rules of the Fire Underwriters were modified so as to require their use. The Rules of the National Electric Code now require outlet-boxes to be used with rigid iron and flexible steel conduits, and with armored cables. A portion of the rule requiring their use is as follows: All interior conduits and armored cables "must be equipped at every outlet with an approved outlet-box or plate.

"Outlet-plates must not be used where it is practicable to install outlet boxes.

"In buildings already constructed, where the conditions are such that neither outlet-box nor plate can be installed, these appliances may be omitted by 6pecial permission of the inspection department having jurisdiction, pro viding the conduit ends are bushed and secured." Fig. 47 shows a typical form of outlet-box for bracket or ceiling outlets of the universal type. When it is desired to make an opening for the conduits, a blow from a hammer will remove any of the weakened portion of the wall of the outlet-box, as may be re quired. This form of outlet-box is fre quently referred to as the type. Other forms of outlet-boxes are made with the openings cast in the box at the re quired points, this class being usually stronger and better made than the univer sal type. The advantages of the universal type of outlet-box are that one form of box will serve for any ordinary conditions, the openings being made according to the number of conduits and the directions in which they enter the box.

Fig. 48 shows a waterproof form of outlet-box used out of doors, or in other places where the conditions require the use of a water tight and waterproof outlet-box.

It will be seen in this case, that the box is threaded for the con du its, and that the cover is screwed on tightly and a flange provided for a rubber gasket.

Figs. 49 and 50 show water-tight floor boxes which are for outlets located in the floor. While the rules do not require that the floor outlet box shall be water-tight, it is strongly recommended that a water tight outlet be used in all cases for floor connections. In this case

also, the conduit opening is threaded, as well as the stem cover through which the extension is made in the conduit to the desk or table. When the floor outlet connection is not required, the stem cover may be removed and a flat, blank cover be used to replace the same.

A form of outlet-box used for flexible steel cables and steel ar mored cable, has already been shown (see Fig. 5).

There is hardly any limit to the number and variety of makes of outlet-boxes on the market, adapted for ordinary and for special con ditions; but the types illustrated in these pages are characteristic and typical forms.

Bushings.

The Rules of the National Electric Code require that conduits entering junction-boxes, outlet-boxes, or cut-out cabinets shall be provided with approved bushings, fitted to protect the wire from abrasion.

Fig. 51 shows a typical form of conduit bushing. This bushing is screwed on the end of the conduit after the latter has been intro duced into the outlet-box, cut-out cabinet, etc., thereby forming an insulated orifice to protect the wire at the point where it leaves the conduits, and to prevent abrasion, grounds, short circuits, etc. A lock-nut (Fig. 52) is screwed on the threaded end of the conduit before the conduit is placed in the outlet-box or cut-out cabinet, and this lock-nut and bushing clamp the conduit securely in position. Fig.

53 shows a terminal bushing for panel-boxes used for flexible steel conduit or armored cable.

The Rules of the National Electric Code require that the metal of conduits shall be permanently and effectually grounded, so as to insure a positive connection f o r grounds or leak ing currents, and in order to pro vide a path of least resistance to prevent t h e current from finding a path through any source which might cause a fire. At outlet-boxes, the conduits and gaspipes must be fastened in such a manner as to insure good electrical connection; and at centers of distribution, the conduits should be joined by suitable bond wires, preferably of copper, the said bond wires being connected to the metal structure of the building, or, in case of a building not having an iron or steel structure, being grounded in a permanent manner to water or gas piping.

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