False positive with volt stick; about 3 V AC on a switched-off cable

Capacitive or inductive coupling to another cable it's running next to - completely normal :)

Agreed, but unfortunate that the volt stick was so sensitive!

Well - it's basically doing what a Neon did, but with less direct contact.

There is a magnetic detector I have that relies on being able to load the circuit with an amp or two - not so handy in this case, but extremely good at pinpointing cables under plasterboard - normally PB lights up detectors for many inches either side of a live cable.

newshound a écrit :

Better a false positive than a false negative (safely off) indication!

It's capacitive pickup. The voltmeter loaded the 120v down to 3-4v.

NT

You still get induction even if the runs are straight, and indeed you still also get electrostatic coupling as well. If you had shorted it all to earth it would probably not have caused any issues and not been apparently live either. Have you ever run your finger over the metal case of a double insulated device with no earth? You can feel a buzz and a small tickle. this is just electrostatic coupling to it from the transformer or psu inside.

I can get a similar feeling with my exposed metal bits of my blind white cane when I'm were walking under electricity wires on a pylon. Indeed, in some places you can strike a fluorescent tube under the wires, but you need to be quite close..:-)

Brian

Hold one of those 2D work lights (they are class II) in one hand and your volt sick in the other hand.

Yes, of course! But it's a bit of a delay in getting the job done.