Just realized you can use a stud finder to locate live wires behind drywall

I was patching up some drywall in my basement last weekend and kept hitting something weird with my utility knife. Turned out I had nicked a romex cable running through the stud cavity. After patching that mess up, I did some digging online and found out many stud finders with a deep scan mode can actually detect live AC wires behind the wall, not just wood. Mine has a little AC warning light I never paid attention to before. I tested it on a known live circuit and sure enough it beeped right where the wire was. Has anyone else used this trick to avoid drilling into wires during a remodel?

3 comments

3 Comments

veram991mo ago

Respectfully, those AC detectors are finicky as all get out and can give false positives if there's any moisture or metal nearby. Your mileage may vary on relying solely on one instead of a proper circuit tester.

casey161mo agoMost Upvoted

Actually had a different take on those detectors until last week. Was wiring in a new outlet and my NCV kept beeping on a dead circuit, turned out there was a pipe in the wall throwing it off. Kinda makes you question how much you can really trust 'em without a backup method.

rowan72519d ago

Agree with @veram99 on this one, I've had my NCV go off on a bone-dry pipe before and felt like a total amateur. Learned the hard way that those things are more of a suggestion than a guarantee, especially around any metal. Guess that's why they call it a "non-contact" detector - doesn't mean it's non-stupid.