PSA: My new non-contact voltage tester gave a false negative on a live 240v line.

I was checking a panel in a Reno house rewire last week, and my tester showed no voltage on a circuit that should have been hot. Went to pull the wire and got a nasty surprise. Turns out the tester's auto-range feature was set to low sensitivity and missed the higher voltage. I learned to always double-check with a proper meter before touching anything, even with a 'safe' tool. Anyone else run into this with the newer auto-ranging testers?

3 comments

3 Comments

jordan_henderson138d ago

Yeah, those auto-range pens are junk for real work. I had a Klein one do the same thing on a 480v feed. It just blinked once and went dark. Now I only use it as a first pass, then I hit it with my actual meter. You can't trust the lights.

the_mia8d agoOG Member

My old Fluke 101 meter did that once on a 277v leg. I mean, it's scary how much you start to trust the little lights. I always do a quick check with my leads now, even if the pen says it's dead.

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rowan_reed688d agoMost Upvoted

That pen light can dim just enough to miss but still carry a lethal charge.