What to do when measuring voltage on nails in the wall?

Question

A while ago, I hammered some nails into a wall trough which wires are running (taking care not to hit any wire).

But when I use a multimeter to measure the voltage between the nail and some other point of the wall I get a reading of 0.89 Volts. When turning the fuse off I only get a reading of 0.38.

This behavior can be observed for various nails in different locations in the wall and does not occur on other walls in the apartment.

I am not sure what to make of it. Is it an error in my measurement or normal behavior when measuring close to a wire? Or do I need to call an electrician asap?

For completeness, here's a picture of my setup and first reading.

I probably have 0.89 volts in my eyelashes. – isherwood Sep 29 '20 at 19:31 — isherwood, Sep 29 '20 at 19:31
it's probably just phantom voltage. – Jasen Sep 30 '20 at 07:47 — Jasen, Sep 30 '20 at 07:47

score 6 · Accepted Answer · answered Sep 29 '20 at 22:11

6

Your photo shows the Red lead plugged into the 10A socket of the meter. Therefore you are measuring the voltage between the COM socket and the HIGH socket on the right which is probably just due to stray 60 Hz fields. Try plugging the RED lead into the HIGH socket and the BLACK lead into the COM socket and repeat your measurements. In all likelihood, they will still be small and just indicate the present of 60 Hz fields from the power lines.

answered Sep 29 '20 at 22:11

Barry

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Thanks! I repeated it and now it reads 2.94V. I also measured between the nail and the grounding and it read 10.9V (1.4 with fuse off). – user4758246 Sep 30 '20 at 06:33
yeah when measuring voltage 10A and COM are basically interchangable. – Jasen Sep 30 '20 at 07:46

What to do when measuring voltage on nails in the wall?

1 Answers1