4 Steps to Test an Extension Cord With a Multimeter

Set your multimeter to resistance or continuity mode Touch one probe to a prong on the male end and the other to the matching slot on the female end. You want near-zero resistance for hot, neutral, and ground.

Check each conductor for broken wires Test hot (smaller prong), neutral (larger prong), and ground (U-shaped prong). Infinite resistance means the wire is broken and the cord is junk.

Verify proper grounding Test between the ground prong on the male plug and the ground slot on the female end — you want near-zero resistance. Then test between the ground prong and both hot and neutral — you should see infinite resistance. Continuity here means a dangerous short.

Test any built-in fuse or circuit breaker separately If the cord has one, check that component for continuity to ensure it’s closed. This takes five minutes and can prevent a shock or fire.