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Had a 200 amp main breaker fail closed during a panel swap last month
It was a standard residential upgrade in a 1970s split-level. The old Federal Pacific panel was a known issue, so we were ready. Shut off the main, started pulling the old breakers, and everything seemed dead. Went to pull the main feeder lugs and got a loud pop and a flash. The main breaker contacts had welded themselves shut internally, so the bus was still live even with the handle in the off position. My heart jumped into my throat. We had to call the utility for an emergency disconnect at the meter, which set the whole job back by four hours. It was a solid reminder to always verify with a meter on the line side of the main, even when you think it's off. Has anyone else run into a main that failed in the closed position like that? What's your go-to double-check method now?
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