Electrical – Wire tone tracer loses signal. Best practices for how to trace an electrical line

electricalswitchwiring

I picked up a Fluke Pro3000 tone tracer to try to trace some electrical wires in my walls, basically to solve some mystery switches and figure out what they are theoretically supposed to control.

The tracer picks up the tone pretty easily near the wires I attach it to at the switch box, but as I move away it quickly decreases in signal and it gets a lot of static. Then if I get far away from any wires, eg standing in the middle of the room, the static goes away too.

I know the wires have to be there because they head up towards the attic through the wall bays. Why would it lose the signal so quickly? And what are some best practices for tracing wire using a tone tracer?

Best Answer

The Fluke Pro3000 is a nice unit, but like other tracers in this segment, it really picks up the signal best when the probe is held within an inch or two of the traced conductor. That's hard to achieve with conductors buried in walls. This kind of tool isn't designed for that job. The nature of building wiring branching out in a star topology going all over also makes it hard to trace a single cable. Fully disconnecting the cable where the transmitter is attached would help combat that, though the signal could branch out as well at the other end of the cable..

If you can get the probe up close and touch the jacket of the cable somewhere else you may get a hit. It could be productive to crawl through the attic to the area where the cables emerge from the wall, probe each of them, and get some idea of the direction the traced cable goes from there.

It might be useful to practice with a cable whose route you do know (or even with a scrap of cable). You could work in an unfinished/semi-finished area of the house to test the detection distance from an exposed cable to the probe, and from cable hidden behind wall board to probe. That'll at least help you set realistic expectations for what the tool may do.