One hour is all it takes to salvage a busted lamp

Table and floor lamps can have a long life. But as they age, their three main electrical components—socket, cord, and plug—may need to be replaced. With a few simple techniques that make sure you do it safely, about $20, and an hour of your time, you can have a like-new, rewired lamp.

Start by unplugging the lamp and removing the shade and bulb. With a screwdriver or a strong pair of hands, remove the upper shell of the socket. The socket shell, the sleeve, and the base (which is usually secured onto a threaded rod with a set screw) can be reused if they’re in good shape. If the shell is metal, make sure that you check that the cardboard insulation sleeve inside is intact.

If you are just replacing a damaged lamp cord, unscrew the wires from the socket terminals. It’s probably best, though, to replace the socket itself while you’re at it, since the switch often breaks over time. In that case, unscrew the socket base from the lamp, leaving the old cord attached. You can use that old cord as a pull wire, attaching old to new, to get the replacement up from the base to the socket.

Whenever you’re wiring, it’s important to know which wire is which. The side of the new lamp cord with raised ridges or printing is the neutral conductor. That wire goes to the silver screw on the socket. The other wire, on the smooth side, is hot; it goes to the brass screw.

With the wires identified and threaded through the secured socket base, pull the two wires apart for a few inches to create two single wires. Then tie them into an underwriter’s knot. If anyone pulls on the cord, this knot prevents damage to the wire or the terminal connections.

Strip the end of each wire, wrap it clockwise around the corresponding terminal screw, and tighten it. Everything else goes back together just as it was when you started.

You’ll save time (and often money) by buying a lamp cord with the plug already attached, but if you’re only replacing the plug, be careful that you attach the wires correctly. It’s the same principle as in the socket. The ridged, neutral wire connects to the wide prong on the plug. Those different-sized prongs mean you can only plug the lamp in one way—the safe way.