Got a nasty shock from a 'dead' panel in an old Philly row house

I was swapping out a breaker in a 1970s panel last Tuesday, and the main was off, meter pulled, the whole deal. My non-contact tester chirped at me when I waved it near the bus bars, which made zero sense. I grabbed my Fluke 87V to double-check, and sure enough, it read 48 volts to ground on what should have been a cold leg. Turns out the neutral from the street was bonded to a different service two doors down through some ancient, crumbling conduit in the shared basement (the place was a total hack job from the 80s). I had to track down the other homeowner, get their power cut for ten minutes so I could isolate and cap that rogue neutral. Has anyone else run into back-fed voltage like that in these old attached houses? What's your go-to move after the non-contact gives a weird signal?

2 comments

2 Comments

reed.eva3d ago

Ever check for shared neutrals with a multimeter first?

henry1013d ago

Forty-eight volts sounds spooky, but is that even enough to get a real bite? Those non-contact testers are basically ghosts themselves, always chirping at phantom voltage. Grabbing the meter was the right call, but sometimes you just get weird induction or leftover static in old wiring. It's good you fixed it, but I'd bet money you weren't in any real danger from that level.