4 Things to Know About Coiling an Extension Cord Under Load

Coiling an extension cord while it’s drawing current can cause dangerous overheating. Heat builds up in the center of the coil because air can’t circulate, and the wire’s resistance turns that trapped heat into a fire risk.

Unspool the entire cord when possible. If you can’t, leave at least a few feet between loops — think loosely draped, not stacked in a pile.

A cord reel designed for continuous use with a built-in thermal switch is the only exception. Even then, don’t fully reel it in while it’s running.

Don’t leave a cord coiled “for a minute” while running a shop vac or heater. Uncoil it.