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So I used a non-contact voltage tester on a dead circuit and it still beeped

I was troubleshooting a dead outlet in a kitchen reno in Spokane, and after shutting off the breaker I checked with my trusty pen tester. It gave a faint beep over the hot wire, which made no sense. I grabbed my actual multimeter and got a solid 0 volts, proving the circuit was dead. The phantom signal was just induced voltage from a live wire running parallel in the same stud bay. Anyone else run into this and have a good way to explain it to homeowners without freaking them out?

2 comments

2 Comments

mitchell.daniel10d ago

Tbh I just show them the multimeter reading of zero volts. I explain the pen tester is super sensitive and can pick up a tiny bit of stray power from a nearby live wire, like a radio picking up a faint station. It's safe because there's no real current behind it, just a ghost signal.

white.grant10d ago

That's a solid way to explain it. I read an article where an electrician called that stray voltage "phantom voltage" or "coupled voltage." It's like when you have two extension cords running together, and the dead one picks up a faint signal from the live one. The pen tester lights up, but a multimeter shows the real story because it needs actual current to flow. Your radio station comparison is spot on.

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