Look over the whole cord, both ends included, before each use, and replace it if you find damage: cuts, cracked or worn insulation, exposed wire, scorch marks, or a loose or bent plug. Don’t tape it. The U.S. Consumer Product Safety Commission says to replace damaged extension cords, never to tape up damaged insulation, and to treat a hot plug, socket or cord as a warning that it may be overloaded or failing. Extension cords are for temporary use. CPSC also says to unplug them when they’re not in use.

Inspect before each use

  1. Unplug the cord and let it cool.
  2. Check both ends for bent or loose blades, a damaged ground pin, cracks, or blackened plastic. CPSC notes that hot plugs and sockets are often caused by deteriorated connections to the cord’s wires.
  3. Run your hand along the jacket and stop at cuts, flat or crushed spots, swelling, or places that feel stiff, sticky or brittle.
  4. Look closely at the first few inches by each end, where the cord flexes most.
  5. If it’s dirty or damp, clean and dry it fully before use or storage.

Replace or keep?

Condition Action
Dirt on an intact jacket Unplug, clean, dry fully, and reinspect
Cut, cracked, worn or exposed insulation Replace the cord
Hot plug, socket or cord in use Unplug it, check its rating against the load, and inspect for damage. Replace if damaged.
Burn marks, melting or a burnt smell Replace the cord, and have the outlet checked if it was involved
Loose blades or intermittent power Replace the cord
Old cord without safety features Discard it (see below)

CPSC says not to alter a cord to change its length, and not to trim, cut or alter the plug blades.

Discard older cords

CPSC recommends discarding cords that are old or missing important safety features, including safety closures, polarized blades, and a large plug face that covers the outlet’s slots and is easy to grip when unplugging.

Match the cord to the job

  • Rating. Check the tag on the cord or its packaging and make sure it covers the products you’ll plug in. CPSC says extension cords should be at least 16 AWG, unless they’re 18 AWG with fuse protection. The wire size is printed on the cord’s surface.
  • Listing. Look for a listing from a recognized national testing laboratory, such as UL, Intertek (ETL) or CSA.
  • Outdoors. Use a cord outdoors only if it’s marked for outdoor use.
  • Routing. Don’t run cords under carpets, through doorways or under furniture.
  • Kids. Keep young children away from cords, and unplug cords that aren’t in use.

Store cords so they last

  • Coil loosely, after the cord has cooled. Don’t wrap it tightly around a tool or a hot appliance.
  • Hang it on a wide hook or lay it flat where it won’t be crushed.
  • Keep it away from heaters, direct sun, sharp tools and chemicals.
  • Dry it fully before putting it in a closed bin.

FAQ

How often should extension cords be inspected?

Inspect extension cords before every use, along their whole length. Add another check after any wet job, pinch, cut, or hard yank.

Can electrical tape fix a damaged extension cord?

No. CPSC says never to perform inadequate repairs such as taping up damaged insulation, and to replace damaged extension cords.

What does it mean when an extension cord feels warm?

CPSC says a hot spot on a cord in use is a warning sign that it may be overloaded. Unplug it, check that its rating covers what is plugged in, and inspect the cord for damage.

Can I cut an extension cord shorter or replace the plug?

CPSC says never to alter a cord to change its length, and not to trim, cut or alter the plug blades. Replace a cord with a damaged plug or socket.

Sources

This is desk research from CPSC consumer guidance. The cord’s own label and instructions control its rating and use.