Continuity and grounding tests are easy with a multimeter.

Yes, you can test an extension cord for continuity and proper grounding with a multimeter in a few minutes.

For continuity, set your multimeter to resistance (ohms) or continuity mode (the symbol that looks like sound waves). Touch one probe to a prong on the male end and the other probe to the matching slot on the female end. You want near-zero resistance for each conductor — hot (smaller prong), neutral (larger prong), and ground (the U-shaped one). If you get infinite resistance, the wire is broken somewhere, and the cord is junk.

For grounding, test between the ground prong on the male plug and the ground slot on the female end. Again, you want near-zero resistance. Then test between the ground prong and both the hot and neutral prongs — you should see infinite resistance (open circuit). If you get continuity between ground and either hot or neutral, there’s a short, which is dangerous. Toss that cord.

One more check: if the cord has a fuse or a built-in circuit breaker (common on heavy-duty cords), test across that component separately to make sure it’s closed.

This takes five minutes and might save you from a nasty shock or a fire.