Had a panel meltdown on a hot Saturday - is it always the neutral or the breaker that goes first?

I was out in Phoenix last August, sweating through a service call on a 20-year-old Square D panel. The main breaker had tripped but when I opened it up, the neutral bar was charred black and the bus looked like it had been through a fire. I replaced the whole panel, but I'm still wondering if a loose neutral causes more damage than a bad breaker, or if it's the other way around. What's your take on which fails worse in these older panels?

3 comments

3 Comments

paulc9316d agoMost Upvoted

and honestly man, I had almost the exact same thing happen last summer with a 30 year old panel in an old apartment complex. Loose neutral was the root cause every time I went back and traced it, the breaker was just doing its job but the neutral arc damage was way worse. In my experience the loose connection at the neutral bar generates heat over time, not just during the fault, so it slowly cooks the bus and can cause way more collateral damage than a bad breaker. If I had to pick which one fails worse in old gear, it's the neutral bar hands down, because the breaker at least trips and limits the carnage.

eva_lewis16d ago

My buddy had a 1985 Square D panel in his duplex that literally caught fire from the neutral bar melting last winter... the breaker never even tripped and it fried half the circuits before we caught it.

parkerb7516d ago

paulc93 you really made me rethink this. Was totally in the "bad breaker is the real threat" camp until I saw a neutral bar meltdown in a friend's rental last month, and it set the whole house smell on fire before we even knew something was wrong. Now I'm definitely looking harder at those neutral connections first, because even a working breaker won't save you from that slow burn damage.