My $80 cable toner saved a full day of tracing wires in an old building

I was working on a retrofit in a 1970s office and the previous installer left zero labels on the panel. The toner let me map every single zone in about two hours instead of guessing and pulling new wire. What's your go-to tool for dealing with messy old installs?

3 comments

3 Comments

wells.anna1mo ago

Man, I read a forum post last week where a guy swore by a simple voltage tester for the same thing. He said in really old places, the toner can get confused by all the weird grounding and phantom voltage. His trick was to just disconnect a wire at the panel and ring it out with a multimeter. Sounds slow, but he said for a real rat's nest it was the only thing that worked.

paul_patel401mo ago

A buddy of mine had a toner totally fail in a pre-war apartment building. It kept picking up noise from the old knob and tube still in the walls. He ended up doing exactly what @wells.anna described, pulling each wire off the terminal and checking for continuity with a basic meter. Took him all afternoon, but it was the only way to get a clear signal. Sometimes the old school method is the right tool.

riley_taylor29d agoTop Commenter

Sounds like a fun way to spend an afternoon. Just you, a rat's nest of old wires, and the ghosts of electricians past.