[Rav]

I've been replacing standard receptacles with GFCI receptacles where needed. I'm currently starting on one in the kitchen. It's on a 20A circuit, a microwave oven and clock radio plug into it, and there are no other outlets on that circuit.

I plugged a receptacle tester in so that when I shut the breaker off, I could visibly see that it was off, and when I did that the tester lights did go out. But when I tested with a non-contact voltage tester, it indicated the hot wire was still live.

It so happens that the wire for another dedicated 20A circuit (the one to the frig) comes in near the one I'm working on. So I wondered whether somehow there was a leak from the frig circuit to this one. I turned off the breaker to the frig, and the NCVT did not alarm.

I next wondered whether this was significant voltage, or perhaps just enough for the frig line to induce a little in the receptacle line. With both breakers back on, I tested the receptacle hot wire with a neon light tester, and it lit up. Then I turned the receptacle breaker off, and the neon light went out. This indicates to me that the voltage I'm detecting when the receptacle breaker is off is enough to trigger the NCVT, but not enough to light the test lamp.

So, the question: In the interest of safety, should I go get a cheap multimeter and verify that any voltage on the hot wire when the breaker is off is minimal, or was the test with the neon light tester enough? Thanks.

 

[Rav]

I should add that the cable is NM 12/2 w/ground. Also, while the receptacle is connected to the cables ground wire, the metal box is not grounded, and I plan to rectify that.

 

[Oso954]

I would suggest that you get an inexpensive analog multimeter. It can make other measurements besides voltage.

One of the reasons I am suggesting analog is that you seem to be confused by indications from high impedance devices such as your NCVT. Almost any inexpensive digital volt meter you find will also be high impedance. The low impedance (or dual impedance) digitals are generally higher priced.

 

[Rav]

Thanks, Oso954. I'm going to go get an analog multimeter and test with that and report the results here.

 

[Rav]

I would suggest that you get an inexpensive analog multimeter. It can make other measurements besides voltage.

I bought an inexpensive analog manual-ranging multimeter and tested with the breaker to the receptacle turned off (and the one to the frig still on). After barely registering on the higher AC voltage ranges, I eventually selected the lowest measurement range (10V max), and it measured at 1 (one) volt between both hot to ground and hot to neutral. Neutral to ground measured zero. I'm amazed that such a low voltage sets off my non-contact tester.

So, I presume this is "ghost" voltage and safe to work with -- agreed?

 

[Oso954]

Yes.

Normally, I won't even change scales on my meter. If I don't see a reading on the 300v scale, I don't worry about it.