30V showing on terminal of 3 way switch when switched off

Question

I have a 3 way switch I am replacing, and found that while testing the old switch, one of the terminals is showing 30v when it's switched off and should be showing 0v. The other terminal correctly shows no voltage when switched off. The situation persisted when I replaced the switch with a new one, so it wasn't a problem with the unit itself, and otherwise the other terminals show correct voltage (and that one showing 30v when off shows 120v when on). I'm assuming that means that I have current coming from somewhere further up the circuit but I'm not sure where it would be coming from. Is this a dangerous situation to be in or can I safely ignore it?

Ed Beal · Accepted Answer

This sounds like phantom voltage. Most meters are high impedance and will show a voltage on a wire that has voltage close to it.
If everything is working properly with your switches there is nothing to worry about.
Phantom voltage can be found all over your home and it is not dangerous.
If your switches are working you can ignore it.

30V showing on terminal of 3 way switch when switched off

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