There is one cable with exposed wires. A voltage tester does not detect anything. Another cable goes into a junction box for the doorbell transformer. The cable in the junction box also has no power.

How can I troubleshoot the two cables with no power? All the breakers in the circuit box are on. Do I need a remote continuity tester? Is that safe to use at the circuit box?

Edit: this is the cable running into the junction box. The other cable with exposed wire is not pictured. junction box

  • Can you provide a picture of the offending wire? Sep 22, 2018 at 22:05
  • And are we talking about a wire (1 wire) or a cable (several wires inside a plastic jacket)? Any writing or lettering on the thing? For scale, shoot it laying across your hand, this will also make the autofocus work better. Autofocus can't target wires. Sep 22, 2018 at 22:10
  • It's a cable with 3 wires inside (see picture). White, brown, and green. Sep 22, 2018 at 22:16
  • Have you tried to follow the cable along the ceiling joist to see where it goes? Possibly it enters a top plate and goes down into a wall where it could be traced to another electrical box.
    – Michael Karas
    Sep 23, 2018 at 15:22
  • @MichaelKaras it goes down a wall with several other cables. I was looking for suggestions on how to trace it at that point. There's only one circuit breaker box. Sep 23, 2018 at 21:03

2 Answers 2


I ended up buying a wire tracer and found the cable led to a bathroom switch. After opening the box I found the cable unconnected. I connected it up and now the doorbell works!


This is a doorbell transformer low voltage 12 or 24v in most cases most non contact testers need ~ 32v to 75v to detect a hot, so your non-contact tester won't think it is a hot but a volt meter will show a voltage.

Is your doorbell working? I would say in 99% of the time this is the reason it works, very common and a non-contact voltage tester can't see it. The primary wiring on the other side is detectable - the cable feeding the box will show hot.

  • The multi-meter doesn't detect any voltage on the old transformer or the new one I replaced it with. With the transformer off a voltage tester doesn't detect anything from the house wires. Sep 23, 2018 at 2:25

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