Buzzing, Blowing Breaker

Feb 21, 2011 39 Replies

I have a circuit that keeps tripping the breaker. I can't find anything wrong in the circuit. There is only a series of lights and a light sensor to turn them on at night. One thing that seems to point me to the breaker itself is that it buzzes when I reset it. It is also an extreeeeeeeeeeemly old style breaker. Breakers shouldn't buzz, right?


Mike D.


No, but I would measure the current draw on the leg.

greg

They often buzz when there is a short of overload on them. It's possible that you have a bad breaker, but more likely there's a problem on the circuit.

One way to find out is to change the wire from one breaker to another of the same capacity. If the swapped breaker still trips, it is the breaker. If the breaker the line was swapped to trips it, it is the circuit.

Or put an Amp meter on the circuit to see what the current is when the breaker is tripping. Repeated trips can damage a breaker, so the breaker should likely be replaced at this point.

You have gotten some excellent advice on how to diagnose this issue... Normally operating breakers shouldn't buzz...

The larger issue here is your "extreeeeeeeeeeemly old style breaker" and this issue might just be the tip of the iceberg... Circuit breakers and the panels they are installed in don't last forever, this might be the first early warning that you should consider planning to replace your entire electrical panel with a new one in the next couple of years...

Good luck...

~~ Evan

I had one that buzzed constantly... turns out the screw that tightened down on the wire apparently was binding and while it was torqued "to spec" it wasn't tight on the wire. Sitting there buzzing for a while apparently loosened it up and when I went back into the panel to do something else I found the screw loose. Tightened it, buzz gone. Was a new Siemens brand AFCI breaker.

nate

Before swapping wires around you need to ensure that you don't overload the neutral. If you don't understand the concept, get help.

On 2/21/2011 3:53 PM Bob spake thus:

Already covered by the phrase "of the same capacity" above. Seems clear enough to me.

"Overload the neutral"??? That is not possible unless the service was installed with an undersized neutral, which wouldn't be to code.

You can certainly unbalance the load between the two hot legs by moving things around, however balance is of no consequence in a residential application, the neutral can handle the full current rating of the hot service conductors and the loads of the two hot legs are not additive in the neutral.

It's also all but impossible to rearrange circuits to overload one leg in a residential application since virtually all large residential loads are 240V and thus balanced no mater where you move their two pole breakers in the panel.

How?

Do tell.

On 2/21/2011 4:43 PM Pete C. spake thus:

Welll, it *would* be possible, say if you connected a 14 ga. hot wire to a 20A breaker, which could overload both the hot and neutral on that circuit (by ~ 5A). But other than that, no, you're correct.

In the event that this particular circuit is part of a multiwire branch circuit, or Edison circuit, it will be sharing it's neutral with another circuit breaker served by the other leg of the service. If the OP unknowingly switches this circuit with a breaker that is not on a leg of the same potential, he will have two circuits of the same potential sharing the neutral, which can cause an overload to the neutral.

All circuits are 20a and not sharing a neutral or ground.

Not possible to swap phases on this ancient beast. All the circuits on one side of the breaker box are on a single phase with the other side on another phase.

I swapped out breakers from another unused box to check. So far, no tripped breaker.

You must have a pushmatic or zinsco panel then. You apparently do understand what Bob was referring to as well.

my neighbor had a killer griswald like christmas light display. he asked for help with main breaker tripping 200 amp main.

me and my trusty clamp on ampmeter found it fast the main was unbalanced.. a few minor changes and all was well.......

so you can unbalance things on a residential service, but it does require effort:)

my neighbor had a killer griswald like christmas light display. he asked for help with main breaker tripping 200 amp main.

me and my trusty clamp on ampmeter found it fast the main was unbalanced.. a few minor changes and all was well.......

so you can unbalance things on a residential service, but it does require effort:)

And how many Edison circuits did you knock out of phase in the process?

If all the circuits on one side are on the same phase, how would you get 240V?

Hopefully it was just a bad breaker. A common reason for buzzing in a panel is when the hot and neutral are in separate pipes.

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