When I turn it off, everything in my home still works. I suspect that it leads to wires that are buried in the wall somewhere. The only problem is that I need more electricity.

So I probably need a tool that can detect electrical wires in walls, with the following requirements:

  • it should detect through wood + drywall (because it's probably behind my kitchen cabinets), so 2 inches may not be deep enough.
  • it should detect live wires only, otherwise it would be very difficult to tell whether I found the right wire.
  • it should detect through the metal shield that usually comes around wires.
  • it shouldn't require to connect the tool to the wire end, because I don't have such an end.

Or maybe there are different methods.

  • What size and type of breaker and what size wire?
    – JACK
    Jul 25, 2022 at 1:28
  • 120v 20 amp breaker. I don't know anything about the wire, but it probably just matches the breaker.
    – George Lee
    Jul 25, 2022 at 1:41
  • 1
    First, check your smokes, CO detector, radon system and other subtle safety systems to make sure they are working. Second, turn the ??? breaker off and leave it off for good. Third, check your smokes, CO, radon again and make sure they're still working. Fourth, live your life. You'll either find something that stopped working, or you won't. Jul 25, 2022 at 6:06
  • When you turn the breaker off, verify the load-side of the breaker has 0V. You have to remove the breaker cover panel to do this-which means: be very careful when you probe, so as to not accidentally short anything or touch a hot circuit. If the breaker is bad (unlikely as it may be), you will still see 120 on the load side. It could also be that the load being fed by this breaker, has been inadvertently also fed by another brkr. Eliminate these possibilities before concluding 'just buried in the wall'. Otherwise, manassehkatz's suggestion to disconnect & label wires is what I'd do.
    – peinal
    Jul 25, 2022 at 11:35
  • Don't forget to think about non-obvious things like a furnace, water heater, attic vent or light, and similar as possible things connected to that breaker.
    – Armand
    Jul 25, 2022 at 13:59

1 Answer 1


Anything is possible. Code says that you can't just leave live wires in walls. They have to end in a junction box and the box has to be accessible. Of course, if your house is like my house, there are probably a few things not quite to code. The problem is that the typical detectors only detect a live wire within an inch or so, both because it is harder to detect from farther away and to avoid excess false positives when working around multiple wires. Plus it is harder to detect a live wire behind a metal plate (as wires should be in certain places for physical protection). So:

  • Check any blank cover plates. Those are often for a junction box that is used to connect two parts of a circuit, but they can also be places that used to have a switch or receptacle or hard-wired device. Open them up and see if you find live wires that turn off when you turn off the breaker.
  • Check inside cabinets. A box is considered accessible behind closed doors, as long as no tools are required to get to it. If a cabinet was placed over a junction box when a kitchen or bathroom was renovated, you may find it lurking inside the cabinet, with a blank plate or a receptacle.
  • Check outside. Outside receptacles often sit unused and forgotten.
  • Carefully remove the front cover of the breaker panel. (You'll need to that anyway when it comes time to actually add a new circuit.) You may find that the breaker is simply a placeholder with no wires attached. Or you may find a label attached to the wires, or (less likely) be able to figure it out from the direction the wires leave the panel.

If all else fails, you could detach the wires from the breaker, cap them with wire nuts, and label them "unknown from breaker 17". Then use the location (with new breaker if a different size is needed) and deal with the problem of a now-dead circuit if/when you ever figure it out.

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