Ah, the joys...I feel like I've lived this story. My house has some very special wiring.
They sell these probes at Home Depot and the like that you can touch to a bare wire end (or, on another setting, hold near an insulated cable) and it will light up and buzz if it's the hot wire of live 120 A/C even if the circuit is incomplete. They're pretty inexpensive and safer than tapping the wires together to look for an arc (and much safer than testing with your hand). You might want to consider grabbing one so it's another thing you can't find easily when you want to do work on potentially live wires.
no subject
They sell these probes at Home Depot and the like that you can touch to a bare wire end (or, on another setting, hold near an insulated cable) and it will light up and buzz if it's the hot wire of live 120 A/C even if the circuit is incomplete. They're pretty inexpensive and safer than tapping the wires together to look for an arc (and much safer than testing with your hand). You might want to consider grabbing one so it's another thing you can't find easily when you want to do work on potentially live wires.