Re: Help: low voltage in circuit, switch off

Basically, your meter is far better than meters of yesteryear. It has extremely high input impedence, so it doesn't 'labor down' the circuit it's measuring, even slightly.

What you're measuring (almost certainly) is a small AC voltage that's induced by the lengths of wiring being in close proximity to each other, much like a transformer. This voltage has no current delivering capability, as can be seen by shorting the wire to ground.

This perplexing phenomenon gives people fits until they understand it.


Steve wrote:
I have a circuit in my house with a funny characteristic, and I'd like
to track it down. In that circuit, I measure a slight voltage
difference between power and neutral at a light fixture when the switch
to that fixture is off. Yet, my meter shows no continuity when I try to
measure resistance. Other circuits do not show any voltage when they
are switched off.

I assume this means that the neutral on the peculiar circuit is not at
a common ground with the 'real' ground. It does not strike me as
inherently dangerous, yet it seems like I might as well sort out the
problem. Anybody seen this and have a recommendation on
troubleshooting?

thanks,

Steve

.

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