We have a customer that has had some strange occurances in his home. Basically, it goes like this: He has an 1100 sq ft house that is 40 yrs old. He has lived there for 30 years. He replaced his subpanel two years ago. The panel looks proper. The senario is: he goes into the kitchen to turn on overhead flourescent light (relatively new). One out of 40 or 50 times he turns on the light it trips the breaker. He then leaves the switch in the on position. Turns the breaker back on, the light still does not come on; however, the breaker does not trip again. He then goes to his 240V window unit A/C, turns that on and the light comes on. I have traced the A/C wiring directly from the panel to the unit. There are no terminations or junctions with any other wire. It is a clean homerun. We have checked voltage, ampacity at the main panel, sub panel, branch circuits and feeder. Everything is as it should be. We have checked all of the lugs. We had the utility company check their transformers. We have checked every junction box, switch box and receptacle for loose connections, etc. We replaced the switch. We put AFCI breakers on all branch circuits.
Any ideas?
Any ideas?