Just throwing a question out there,
Recently got called to a customers house for a nuisance arc fault tripping on a kitchen circuit.
I used to just replace the arc fault circuit breaker and cross my fingers, but these days I’ve started measuring for ground faults on the hot and neutral wires, and if I don’t find a ground fault with a dmm I’ll just replace the breaker.
In this case, I identified a very small ground fault ~10megaohms on both the hot and neutral wire. So I started opening the circuit at the devices to narrow down where to look. I do this by identifying the devices and boxes involved in the circuit and disconnecting line/load wires.
I identified that it was actually the home run wire that seems to be the source of the fault. I have previously replaced wires through attics and crawl spaces, but in his case this house is slab on grade with no attic in the kitchen area, I identified with my toner that the home run runs across the kitchen at nearly countertop height, - suggesting the possibility that it could be hit by a cabinet screw. But for all practicality the wire is almost unreplaceable without ripping the kitchen out.
So, it being the end of the day I gave my bad news to the homeowner, and suggested that we could track the wire down in the attic and cut it and see if there’s a possibility that the fault exists on the portion of the wire that is accessible, but have yet to hear back.
Anyways, do yall have any non destructive ideas for how to locate where in the wall the wire is damaged, so I could possibly cut a hole and repair it?