How can I work out where an electrical cable runs through walls/floors?
I am building a circuit map of a 1941 house with unfinished basement. I shut off all circuits at the main service panel, switch on the circuit I wish to trace, and track the cable from the panel and through the basement till it disappears into the floor above, then run upstairs and see what's powered and tag it. 2 cable runs I have tracked to where they disappear into the wall/floor leaving the basement and lost there. Checking outlets (switches/receptacles/luminaires) throughout the house indicated none were powered by the circuit.
Is the only option to start cutting holes in the wall and hope I can pick up the path of the cable run from there?
EDIT: Would an analog tone and probe kit work? I guess I would switch off main breaker, pop the service panel, and hook up the probe directly to the start of the circuit within the panel, then chase the tone through the walls?