Hey guys. Hope you can help me. I have a home that definitely has a buried junction box in the drywall. The wires are live and are feeding a chandelier and pot lights. Some load, but not a huge amount. Its an expensive home and I don't want to start poking holes in the drywall. Thermal gun? I spoke to a person in the field and he said it wouldn't pick it up unless there was a massive load or bad connection creating a lot of heat. Any suggestions for electronic tracing devices? Thanks in advance
If it's a metal junction box that's buried a stud finder should have some reaction. Generally it detects the increased density of the wood but there's a chance that it would also give some lesser indication when it encounters a metal box between studs. Once you narrow it down you can drill a small hole and look inside the wall with a borescope to try to get the exact location.
I had a job that was very similar to this some years back. Not wanting to buy a proper metal detector, I made up a small oscillator that had a coil of wire on a plastic former attached to it, after some initial workshop testing, I took out to the job, long story short, it took a matter of seconds to find the offending joint. It's pretty poor form joining stuff in a wall though, all the same.
I love my tone tracer! It even works with wires inside Bergmann conduit (Orangeburg pipe with a thin outer coating of sheet metal, not earthed) in plastered brick walls. I only have a rather inexpensive one, 85 Euros. Allowed me to spot a buried splice +/- 1 cm! Some moron moved a door (and light switch) by just splicing new wires to the old cloth-covered ones and plastering over the old switch box. I found the splice, patched in a new section of flex conduit instead of the box, pulled new wires through the now complete conduit run and that was it.