Garage circuit breaker problems.

July 14, 2008 7:16 AM

Garage circuit breaker keeps tripping...

We had some work done in the backyard (new patio). The workers dug around the cable of wires going to the garage, careful not to damage it. As far as I know, they didn't.

Ever since that first dig, the breaker to the garage consistently trips. Sometimes it's two minutes, sometimes it's six hours.

I looked at the box going out of the house, it looked fine to my untrained eye (wire caps in place, etc.).

It's a 15 amp breaker.

My main question: Would slicing that cable cause a breaker to randomly trip?

Any other theories? Lightning maybe? If the wire is fine, should the breaker just be replaced? If it was the wire would stringing a new one around the new patio be the easiest solution? I'm still talking with the landscapers to fix this, too.

posted by starman to home & garden (11 comments total)

If it is an older wire it may not be of the type that can be used underground. Disturbing the cable may have been enough to cause a break that eventually gets hot enough, or arcs, to cause the breaker to trip.
posted by Gungho at 7:32 AM on July 14

You mentioned lightning, which suggests rain. Could it be happening most often when the ground is wet?
posted by jon1270 at 7:39 AM on July 14

Time to get an electrician and stop resetting that breaker. If it fails to trip your house could burn down.

Other than digging near the buried service did you add anything to the circuit, a new outside lamp etc.? If so you might look there first, say by disconnecting it and seeing whether the breaker trips. Make sure you are around during such a test such that if anything happens you can shut the power or even put out the flames.
posted by caddis at 7:48 AM on July 14

It's probably 10 years old. It looked like a solid bundle of cables, Gungho, but again, I'm not an expert.

It's been mostly dry, jon1270...

Yeah, I'll leave the breaker off. And no, nothing else was added and as far as I can tell, the garage is the only thing on the circuit.
posted by starman at 7:54 AM on July 14

Is it possible that the wires are touching the concrete? Concrete is highly alkali, and can eat away at the insulation of older cables.
posted by Pastabagel at 8:16 AM on July 14

Circuit breakers sometimes fail. It's happened to me a couple of times. Breakers are reasonably inexpensive, so before you incur the expense of an electrician's house call why don't you replace it? You can find instructions here.
posted by Neiltupper at 8:26 AM on July 14

is it a GFCI breaker? does the little button pop out or does the lever end up in the middle?

i would look at possible leakage (water type) on any outside outlets, but the problem is probably some damaged insulation. probably time for a new cable out to the garage.

a small nick in the black (hot) wire will bleed to the dirt especially if it's moist. it takes quite a bit to trip an old-style breaker, a tiny tiny amount to trip a GFCI.
posted by KenManiac at 8:30 AM on July 14

KenManiac has it, I think. Clearly it's related to the dig, it was not happening before. Garage and other exterior outlet circuits are required to be GFI under most electrical codes, so if it's only 10 years old, it probably is GFI.
posted by beagle at 9:07 AM on July 14

It's not touching concrete...

It's the switch that ends up in the middle... it's in our main breaker box.
posted by starman at 9:29 AM on July 14

Some GFCIs are at the circuit breaker and may not have a pop-up button on an outlet. It's tripping because somewhere, current is leaking to ground. An electrician should be able to determine which wire it is, and whether you need to dig to find it.
posted by beagle at 10:36 AM on July 14

Just for the record the electrician bypassed the wires under the patio and it works fine now. Must have been nicked.
posted by starman at 2:25 PM on August 2