Problems with circuit breaker tripping

Rd1234 · Jul 27, 2020

I have a circuit on my back patio that keeps tripping periodically. No apparent reason, it just trips when nothing is on

telectrix · Jul 27, 2020

could it be during or after rain? do you get rain in Az?

Rd1234 · Jul 27, 2020

telectrix said:
could it be during or after rain? do you get rain in Az?

No rain doesn't rain here been more that 100 says without rain this time
[automerge]1595858023[/automerge]
No rain been over 100 says since last rain.

telectrix · Jul 27, 2020

gophers nibbled cable/s?

Rd1234 · Jul 27, 2020

telectrix said:
gophers nibbled cable/s?

Everything is in conduits from panel

pc1966 · Jul 27, 2020

Could be ants/termites in some cable junction box, or a cable that has been crushed or otherwise physically damaged. Starting point would be to inspect as much as you can sensibly access, and if opening any covers / removing sockets to look inside make very sure the power is off.

If you can't see any oblivious damage then you really need yo get a professional electrician who can do a high voltage insulation resistance test to see if the cables / accessories are OK, and if no fault is found on the wiring / sockets / etc then it might just be a faulty GFCI.

Rd1234 · Jul 27, 2020

pc1966 said:
Could be ants/termites in some cable junction box, or a cable that has been crushed or otherwise physically damaged. Starting point would be to inspect as much as you can sensibly access, and if opening any covers / removing sockets to look inside make very sure the power is off.

If you can't see any oblivious damage then you really need yo get a professional electrician who can do a high voltage insulation resistance test to see if the cables / accessories are OK, and if no fault is found on the wiring / sockets / etc then it might just be a faulty GFCI.

Not termites or ants everything is metal above ground. All three circuits run from panel, in 1 inch electrical pvc, to patio them above grade conduit is metal run to metal boxes. Patio is all metal. Everything grounded at each box. Also when installed I made sure not to cross Commons, so there are 3 Commons and three got wires, different color for each to keep straight. The interesting or confusing part it that when you reset the breaker it works fine for a couple of months then all of a sudden when you try to turn on a light the breaker is tripped again. Have already tried replacing breaker did not seem to help. There is 2 boxes I hadn't checked yet, would a short periodically trip the breaker when nothing is on. I have rewired everything on that circuit except they the two junction boxes where the circuits branch off

pc1966 · Jul 27, 2020

Rd1234 said:
Not termites or ants everything is metal above ground. All three circuits run from panel, in 1 inch electrical pvc, to patio them above grade conduit is metal run to metal boxes. Patio is all metal. Everything grounded at each box. Also when installed I made sure not to cross Commons, so there are 3 Commons and three got wires, different color for each to keep straight. The interesting or confusing part it that when you reset the breaker it works fine for a couple of months then all of a sudden when you try to turn on a light the breaker is tripped again. Have already tried replacing breaker did not seem to help. There is 2 boxes I hadn't checked yet, would a short periodically trip the breaker when nothing is on. I have rewired everything on that circuit except they the two junction boxes where the circuits branch off

If you can get someone to do an insulation test that would be a useful confirmation that both the L & N are really isolated from E (ground).

The other possibility is the GFCI is being tripped by voltage spikes. Lightning is an obvious source but maybe not in your region, or someone with large motors being switched on the same power feed as yours.

Do you have surge protection fitted to your main DB (panel)?

See also this thread: