I'm currently building an addition to our house and in the final phase of wiring - installing the switched, receptacles and fixtures. I am running into an issue and was hoping to get some help troubleshooting this. I have 3 light circuits - one for the garage and exterior lights, one for the lower level, and one for the upper level. These are all on 15 amp SquareD QO CAFI breakers.
I had the garage part already wired and working properly, as well as the upper level. Yesterday, I installed switches in the lower level. There is one pair of 3-way travelers going from a box on the garage circuit to a box on the lower level circuit. I am however not using this set, I am only switching those lights from the garage box currently (the cable - NM-B 14/3 with ground - is just for future use if we decide to not use motion sensor lights).
I had by accident tied the neutral from that set in with the neutrals in the box for the lower level. When I went to turn the garage breaker on, it tripped immediately. I then figured out my mistake and removed the garage-circuit neutral from the lower level bundle. I could now turn on the garage breaker. But when I try to turn on the lower level breaker, it trips right away.
I went through the steps for the QO time saver diagnostics and it trips at 0 seconds, indicating one of the following:
Arcing to ground Shared neutral Grounded neutral Ground fault
My plan now, instead of removing all my switches, I would start in the middle of the run, disconnect a set of load wires, and see if it still trips, indicating which half of the circuit the problem is, and continuing like that, inspecting all my previous work. I do have a DVOM, and a circuit traver available. My questions are:
- What should I look for specifically? My theory is maybe a bare ground slipped and is touching a hot or neutral.
- Does the diagnostics indication from the breaker make sense with the previous issue in mind (other breaker tripper when neutrals were connected)?
- Is there a quicker/easier way to troubleshoot this then my idea?
- Is my idea the "correct" way to troubleshoot this?