I was replacing light switches in my house last night. I went to the panel and shut off the breaker for the circuit I was going to be working on. I verified the lights and fan did not turn on as my check that power was indeed off. I started unscrewing the 3 switches at this location and was greeted with a shock part way through.

I grabbed the multimeter and found there was a reading of 7 volts between the black and red wires running to the 3 way switch across the room, when checked with the neutral from the incoming power line (for the breaker that was off). Through troubleshooting I found another breaker in the main panel, that when off, would result in the 7v reading going away.

As I was replacing this 3 way circuit with Leviton's smart switches, I was using a wireless switch on the other end anyway, so I capped off every conductor on that cable on both ends, and tucked it away in the back of the boxes.

How would this leaking voltage be possible? Furthermore, if it's coming from that other circuit, as it seems to be, why would it only be 7v?

Thanks for your help!

  • measure the current of the 7v with your meter, I bet it's negligible...
    – dandavis
    Commented Feb 2, 2023 at 23:19

2 Answers 2


Nothing to worry about. Induced voltage from other circuits, undoubtedly at very low power -- if you measure that voltage across any load I bet it'd drop like a rock.


Phantom voltage.

Usually small voltage/weak power induced in disconnected(breaker off) wires by close by live wires.

Turning off the other breaker almost proves this.

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