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Simple incandescent lamps consist of three basic electrical parts: the plug, the cord and the socket. When the lamp fails to work, one or more of these components is defective.

Begin troubleshooting by examining each part.First inspect the plug. Often the lamp failure may be caused by prongs that are not making contact in the wall outlet. The problem may be that the prongs are too close together. Try bending them apart to insure a tighter fit in the outlet. Dirty or corroded prongs will not conduct electricity, so sand them with fine sandpaper. If the prongs are loose or if the plug casing is cracked or broken, replace the plug with a new one. Depending on the style of lamp, you may want to use a plug with screw terminals or a quick-connect plug as a replacement.

To rewire a screw-terminal plug, first cut the old plug from the cord with a pair of wire cutters. The cord will most likely be made of flat rubberized insulation with two wires inside.

Pull the wires apart so that they are separated for about two inches. With a sharp knife or wire strippers, strip 3/4 of an inch of insulation from the each wire; be careful not to nick or cut the wires.

Push the cord into plug so that the bare wires emerge near the screw terminals. Some plugs have clam-shell casings that are held together with one screw.

Remove the screw and the casing, then position the wires near the terminals. Twist the wires clockwise around the terminal screws and tighten the screws to secure the wires.

If the lamp is relatively new, the plug will be polarized with one prong wider than the other. The replacement plug may, or may not, have this wide prong (the National Electrical Code does not require replacement plugs to be polarized. If it is a polarized plug, connect the neutral wire to the wide prong. At first glance, both sides of the cord may look identical; but a closer inspection will reveal that one side, with the neutral wire, will have identifying marks like ribs, indentations or square corners on the insulation.

Quick-connect plugs are easier to connect than screw-terminal plugs. It's not necessary to separate or strip the wires, but the cord should have a clean-cut end. There are different types of quick-connect plugs, and the hook-up varies with each type; but instructions are included with the plug. These plugs are rarely polarized, so you don't have to worry about the neutral wire.

If the socket is defective, replace it with an identical model. Lamp sockets, whether push button rotary, or three-way switch models, consist of four parts: the outer shell, the insulating sleeve, the socket and the base cap. Before removing the old socket, check that the lamp is unplugged.

Pull the outer shell off the old socket, then the insulating sleeve. Loosen the terminal screws on the socket to disconnect it from the wires. Remove the base cap by loosening the small set screw that holds it to the lamp.

Installing a new socket is essentially the reverse of the above procedure. Thread the wires through the base cap and secure it on the lamp. Before fastening the wires onto the socket, make sure that they are tied in an underwriter's knot.

The socket has a silver and a brass terminal. The neutral wire should be connected to the silver terminal. Wrap the wires clockwise around the screw terminals, then tighten the screws. Slide the insulating sleeve over the socket, then press the outer shell in place. Voila!