Electrical – Outlet box has voltage when a device is plugged in on another circuit

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Our house was built in 1964 and I wanted to replace some of the electrical outlets. However, there's something bothering me.

When I turn off the circuit for an outlet, my low range non-contact voltage tester picks something up on the metal outlet box. After some testing, there's a few outlets that have this issue. What's strange is that the beeping on the tester increases in frequency in some situations. For example:

  1. I plug in something in another outlet on another circuit.
  2. I turn on or off or dim lights on another circuit.

I don't have a proper tool to measure the voltage. I'm considering a multi-meter, but I am getting into uncomfortable territory.

An outlet tester indicated that all outlets are wired correctly, except for two that had an open ground. I was able to correct one (the original copper wire broke) but the other one looked fine. I am not sure if this could be related. I will be hiring an electrician, but I'm looking to understand whether or not it is normal for the metal box to have some amount of voltage.

Additional Information: We did identify two receptacles that are "hot/neutral reversed". They were originally unnoticed because they were both upside-down. I am not sure if this could contribute to anything. We'll be hiring an electrician in a few weeks and I'll update the question once I have a response.

Best Answer

This very much sounds like a case of what is called Open Neutral. This can be a very serious condition, depending on where it is. Where you plug something in that results in a voltage somewhere else, do plugged in equipment or lights operate properly?

An Open Neutral is when the neutral wire of a circuit is disconnected or not making proper contact. The result is the one or more receptacles are in series with a different group of on or more receptacles and 240 volts is being applied. If the loads are unequal, one load will get a higher voltage (more than 120 volts) than the other. Where more than one load is in a group, shutting of or unplugging one thing can raise the voltage on others in that same group.

This condition requires a licensed electrician to resolve. The only action you should consider, in the mean time, is shutting off the main breaker or main disconnect or pulling the main fuse block.

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