I was in the shop Monday and I heard a pretty good bang in the shop. A 30 amp breaker tripped and won't reset. Is this a common issue?
Something shorted to ground, that was the bang.
Cooked the internals of the breaker in the process, or is still in a state that the breaker won't reset. Investigate what the breaker feeds, rule out all issues and then try the breaker. Replace if still bad.
Wait until you're around when it happens to a 480v 600A feed, that'll make you jump!
I know the circuit feeds three receptacles on the west wall, i.e. a small water heater on one recept and the ceiling fan, stereo etc on the other two?
Sounds like a code violation to me.
Charles
I know the circuit feeds three receptacles on the west wall, i.e. a small water heater on one recept and the ceiling fan, stereo etc on the other two?
Sounds like a code violation to me.
Charles
Something shorted to ground, that was the bang.
Cooked the internals of the breaker in the process, or is still in a state that the breaker won't reset. Investigate what the breaker feeds, rule out all issues and then try the breaker. Replace if still bad.
Wait until you're around when it happens to a 480v 600A feed, that'll make you jump!
480s got nothing on 138kV. Was standing in a station when a tent blew into a 138kV bus. Not fun.
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480s got nothing on 138kV. Was standing in a station when a tent blew into a 138kV bus. Not fun.
That's a good way to soil the rear of your arc flash suit
No open short in the heating element, showing 7 ohms? I unplugged everything on the circuit and the breaker will reset.
No open short in the heating element, showing 7 ohms? I unplugged everything on the circuit and the breaker will reset.
), then the circuit breaker itself and the circuit wiring -seem- to be OK.No open short in the heating element, showing 7 ohms? I unplugged everything on the circuit and the breaker will reset.
Water heater likely drew too many amps and blew the breaker. Plug everything but the water heater back in and it will probably be fine. You really should run a dedicated circuit for the heater, and swap the 30a breaker for a 20a breaker (as long as you have at least 12ga wire) to protect the outlets.
Drain the water and pull the lower element out and look it over.![]()

Breakers that trip from overload, don't go "bang". They just trip, quietly.
There is a short or ground fault issue along with the obvious "plugging household 120v appliances into a 30 amp circuit issue."
This might be the problem!
This is a good one. I thought the post was about a circuit breaker. When it is the circuit breaker that is the only thing working like it is meant to. When I did inspections it would be called undersized branch wiring if the breaker was sized to large. I don't know what size the wires are, but, ya there are a lot of other things wrong.![]()
This is a good one. I thought the post was about a circuit breaker. When it is the circuit breaker that is the only thing working like it is meant to. When I did inspections it would be called undersized branch wiring if the breaker was sized to large. I don't know what size the wires are, but, ya there are a lot of other things wrong.
I know lots of things that I should do/change too, and some day I will get to them.
Good Luck







Replace the breaker with a 100A breaker.
That way next time the extension cord shorts you will have enough current to burn the short clear!