Rewire every lamp you buy secondhand. Cords and sockets are the parts that fail, they're inexpensive to replace, and they are the only parts of a lamp that can hurt you. The rest of the lamp, including a brass base from the 1930s, is usually fine.
Unplug it before you touch anything, and keep it unplugged until the work is finished. The inspection itself takes a minute: run the cord through your fingers and look for cracks in the insulation, check where the cord enters the socket and the base for a worn spot, and look inside the socket for a cracked shell or a scorched contact.
The one wiring rule that matters most
In a screw-in socket, the outer metal shell must connect to the neutral conductor and the center contact to the live one. That way the exposed threads are never live when the lamp is switched on, which is what makes changing a bulb with the switch left on survivable. Everything else in this column is a preference. This is the rule. On a US plug, the neutral blade is wider than the hot blade, so a polarized plug only goes in one way; many plugs have been polarized since 1948. That's how this rule survives at the outlet.
What to check, and what the answer should be
| Part | What to look for | If it fails |
|---|---|---|
| Cord insulation | Cracks when you flex it between finger and thumb | Replace the whole cord. Taping a cracked flex is not a repair |
| Plug and polarity | Ribbed conductor to the wide blade, and a ground pin on metal lamps | Fit a new plug, and use three-core flex on any metal body |
| Socket shell | Cracks, scorching, a loose fit on a bulb, or a felt-like texture | Replace the socket. Bakelite cracks with age and cannot be repaired |
| Strain relief | A grip where the cord leaves the socket and the base | Fit a cord grip or bushing. A knot inside the base is a poor substitute |
What to replace, and with what
- Cord and socket, every time — 18-gauge lamp cord suits any household bulb. Fabric-covered twisted cord looks right on an old lamp and is easy to find by the foot.
- A socket with a switch, or a cord switch — Either works. A cord switch keeps the original socket and is simpler; a switched socket is cleaner and slightly more expensive. Both are rated far above the 0.5 amps a 60 watt bulb draws.
- A ground on any metal lamp — A metal body should be grounded, which means three-wire cord and a three-prong plug. A double-insulated lamp carries an insulated body and a double square mark and needs only two cores.
- Nothing else, usually — Shades, harps, finials, brass bases and even most switches survive. The exception is a socket made of brittle resin or a cord that has gone stiff and shiny with heat.
Putting it back together
Rebuild in the reverse of the order you took it apart. Feed the new cord through the base, fit the strain relief, strip about half an inch of insulation, and tighten the terminals so no bare wire can touch the other terminal or the shell. Then check with a multimeter before you put it back together.
Six things to buy before you start
The whole kit costs less than an electrician call-out, and a rewire is a short job once the parts are on the table. Prices are shown only where we confirmed them on the brand or retailer page in Oct 2026.
Start hereGardner Bender
Lamp Cord Set, 18 gauge, 8 ft
One purchase covers the two parts that fail. Check that the shell is a screw type rather than a push-in, which strips more easily.
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Vintage
Fabric-covered twisted cord, 10 ft
A modern white cord on a brass base looks like a repair. Twisted cloth cord in a period color costs a few dollars more and dresses the whole object.
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Leviton
Phenolic Lamp Socket, 3-way
Phenolic takes heat better than the resin in cheap sockets and does not become brittle. A three-way socket works with an ordinary bulb as well.
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Klein Tools
Digital Multimeter MM320
The tool that turns guessing into knowing. A continuity check proves the shell is bonded to the neutral and that nothing shorts to a metal base.
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Vintage
Brass table lamp, base only
Mid-century brass and ceramic lamps are cheap because nobody wants to do the wiring. A cut cord lowers the price further and the fix is fifteen minutes.
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Pleated silk shade
Old shades are often marked for 40 watts, and a 100-watt bulb can scorch the lining. Fit an LED, which runs far cooler.
Compare listingsWhen to call an electrician
- 1
If a metal lamp has no ground
A brass or steel body with a two-core cord is not a lamp to use, it is a lamp to rewire before it is switched on. If in doubt, an electrician will do it in half an hour.
- 2
If the socket is fixed rather than removable
Some lamps have a socket riveted into the base. That is a bench job with the right tools, and a shop will charge less than it takes you to improvise.
- 3
If the lamp is an antique with a fabric cord
Keep the original cord if the lamp is valuable and use it for display only. Never run current through a fabric cord that has any age on it.
- 4
If it is going into a rental
If you're renting it out, landlords may want proof the work was done properly. Keep the receipt for the parts as evidence of the work.
The economics are simple. A vintage brass lamp with a cut cord is often cheap at a flea market, and the same lamp rewired and working sells for several times as much (estimates, Oct 2026). A small kit of parts and an evening is the whole difference, which makes old lighting one of the best categories in secondhand furniture rather than one of the worst. Standard US household bulbs use the E26 medium screw base, named for its 26-millimeter diameter, so replacement sockets are easy to match.
