Is my voltage-check pen wrong?

Question

I am trying to work on a light switch in my new house. After turning the power off to the room in question (from the circuit breaker) and unscrewing the plate off the switch, the pen still lights up (faintly) when I touch it to the wires inside the switch. Is this normal?

In addition, get this: I turn the power back on at the breaker, and just for yaks, I touch the pen to the outside screws (the ones that hold the cover plate) and the pen still lights up! There should not be any voltage there, should it?! I mean, I can touch those outside screws and nothing happens!


Dragos (electrical work wannabe newbie)

Thank you guys, I will actually check what the voltage is at the switch, to make sure I don't get electrocuted working on it.

Answer 1

You have a wire going to ground somewhere. It's not enough to trip the breaker....but just enough to give you a bleed through. Those things are hard to find...and it could even be someone has rewired something in your house backwards...which can cause this. Good luck in finding it....they are hard to trace. Bad thing is...if you don't find it and someone has wet feet and touches one of the ground areas...they could be shocked.

Answer 2

Yes, this is normal. The pen picks up EMF, electo-mechanical-force. Static electricity can do this also.

The only true way to know if the voltage is off, is to use a volt meter.

Answer 3

If you mean your newly built new house, then contact the builder. It is miss wired someplace and takes an electrician to find.

He would isolate it at the circuit breakers then trace it down.

Answer 4

Throw that thing away before it gets you killed. Check for voltage with a voltmeter.

Answer 5

It sounds as if you have a switch that is wired 'backwards' & you have the ground loop engerized with power.

good searching..