Had a close call with a 277v lighting circuit in a Chicago high-rise last month

We were swapping out old fluorescent fixtures for LEDs on the 15th floor. My apprentice went to test a circuit he thought was dead, but the building's lighting panel schedule was wrong. His meter read 277v to ground when he expected 120v. The shock threw him back about three feet, but his gloves saved him from worse. Now I make my crew verify voltage with two different meters before anyone touches a wire, no matter what the prints say. How do you guys handle bad panel schedules in old buildings?

3 comments

3 Comments

murphy.aaron26d ago

Honestly, how do you even start tracing wires in a mess like that? Tbh I'd be worried about hidden junctions or abandoned lines still being hot. Sounds like a nightmare to sort out.

patricia_gonzalez26d ago

My uncle's an electrician and he told me a story about a hospital rewire where the panel labels were from a renovation in the 70s. They found a whole bank of circuits marked "spare" that were actually live feeds to the old nurse call system. His rule now is to treat every unknown wire like it's hot until you prove it's dead with your own tester, then prove the tester works on a known live source right after. It's that "test, test, test" habit that saves fingers.

dakota41526d ago

Spare" is the most terrifying word you can read on a panel label, right up there with "miscellaneous." Of course the 70s renovation crew just slapped that on there and called it a day, probably thinking future people would have cool x-ray vision. Your uncle's rule is the only way, because trusting a faded sticker from the disco era is a fantastic way to make your day very, very exciting.