What Bulb For

Why is my extension cord hot?

A cord that’s hot while in use is a warning sign that it may be overloaded. Unplug it, check its rating against what’s plugged in, and look along its whole length for damage.

What to check

  1. Too much plugged in

    How to tell: Most of the cord is warm or hot while things run. Overheating is usually caused by overloading, or by plugging in appliances that use more watts than the cord can handle.

    Fix: Read the rating on the cord’s tag or packaging and add up the watts of everything plugged into it (the watts to amps calculator takes a sum). Unplug something, or use a cord rated for the load.

  2. A cord too light for the length

    How to tell: A long, thin cord on a big load, such as a power tool. An undersized cord loses voltage and overheats.

    Fix: Use a heavier cord, a lower gauge number. See the extension cord gauge chart.

  3. Hot at the plug or the socket

    How to tell: Only the plug, or the socket end, is hot. Hot plugs and sockets are often caused by deteriorated connections to the cord’s wires.

    Fix: Replace the cord.

  4. Melted, cracked or worn

    How to tell: Soft or melted plastic, a plug melted to another plug, cracks, or bare wire. Damaged extension cords can also cause fires.

    Fix: Replace the cord. Never tape up damaged insulation or cut the plug. Don’t use the appliance whose plug melted until it has been checked.

  5. Covered up

    How to tell: The cord runs under a rug, a carpet or furniture, or through a doorway.

    Fix: Move it into the open. Extension cords shouldn’t run under carpets or furniture, or through doorways.

Space heaters go straight into a wall outlet, never an extension cord: see space heaters and extension cords.

A hot wall outlet

If the wall outlet itself is hot, stop using it and call an electrician. Don’t open the outlet or its cover.

For something that’s always plugged in

Extension cords are meant for temporary use. Where something needs power all the time and there’s no outlet near it, an electrician can add an outlet.

Unplug a hot cord at once, pulling on the plug, not the cord, and don’t use it again until you’ve found the cause.

Common questions

Can a hot extension cord start a fire?

Yes. Extension cords can overheat and cause fires when they're used the wrong way, and damaged ones can start fires too.

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Keep going

Extension cord gaugeWatts to ampsPower strip into an extension cordSpace heaters

Where we get our information from

The warning signs and what to check come from the CPSC’s extension cord fire safety sheet, with a tool maker’s manual (DeWalt) on undersized cords and OSHA on unplugging. Checked against published data from CPSC, DeWalt and OSHA.

See all 5 sources
  • US Consumer Product Safety Commission, “Household Extension Cords Can Cause Fires” (Pub 5032): the rating on the tag, hot cords, at least 16 AWG, temporary use, cords marked for outdoor use, not through doorways
  • DeWalt, DWS713 miter saw instruction manual (2023): “Minimum Gauge for Cord Sets” table
  • OSHA, “Extension Cords: 5 Things to Know” (OSHA 4495): 3-wire extension cords and grounding, wet connectors
  • US Consumer Product Safety Commission, “Keep Warm and Safe This Winter” (January 2026): space heaters directly into a wall outlet, three feet, off when sleeping; portable generators at least 20 feet from the home
  • US Consumer Product Safety Commission, “7 Highly Effective Portable Heater Safety Habits” (NSN 15-11)

General guidance from manufacturer and standards data. Products vary, so check the label and the maker's instructions.