To sort out breakers in a panel I use a high tech device, a radio! Plug it
into the outlet, turn it up so you can hear it in the mechanical room and
start flipping breaker untill it goes off. Same with light fixtures, but I
have a light socket adaptor to plug the radio into.
I have been on construction sites and seen electricians do the same! One
electrician commented a simular experiance with the high tech circuit
tracers, he claims a loud radio has yet to fail him!
Greg