[rexnance]

I've got a branch circuit that has started tripping the gfci breaker any time a light is turned on, here's what I know.

1. The house is about 2 years old, the circuit has been working until yesterday
2. The circuit covers two outlets, two separately switched light fixtures and an exhaust fan in a bathroom plus 3 outlets and two separately switched ceiling lights in the hall area.
3. I've swapped the hot and neutral wires with another bathroom gfci breaker and the problem follows this circuit
4. With no load on the circuit the breaker doesn't trip and I can measure voltage at all receptacles and light switches.
5. As soon as any light switch is turned on, the light flashes and the breaker trips. Additionally, I can take a small lamp and plug it into any receptacle and it will also flash on and then trip the breaker.

Any ideas regarding troubleshooting steps?

Thanks!

 

[joed]

Sounds like a ground wire may be in contact with a neutral somewhere. Try splitting the circuit in sections and isolate which section has the problem.

 

[jbfan]

Is it a gfci, or an afci?
The troubleshooting will be the same either way.

 

[rexnance]

Not sure if i'ts a combo afci / gfci. I did find the issues in a light can where the ground wire was touching the common leg. Not sure how these things move over time but it clearly did.

Thanks for your help!