Arc Fault Tripping

[NMeyer]

I recently upgraded my service panel and in doing so added cafci circuit breakers in my panel where required. One of these circuits trips as soon as the lights supplied by it are turned on. The circuit supplies only lighting on one level of the house which consists of 12 recessed cans split between two sets of switches. One switch leg controlling 4 cans and the other controlling the remaining 8. The house was built in 2016 and this circuit was holding just fine on a standard 15 amp breaker. I have gone through all the switch boxes and cannot find any neutral or ground issues or see any signs of a short. I have also gone through the group of 4 recessed cans and could not find any issues in the individual junction boxes for each light. And yet as soon as either set of cans is turned on the arc fault breaker trips. Any help would be appreciated

 

[tom baker]

Try a GFCI see if it trips, if so have a neutral ground somewhere

 

[synchro]

Perhaps the lighting is getting its neutral from another circuit. If so, then a GFCI breaker (as Tom suggested) would also trip when a light is turned ON. If it trips a GFCI, try a regular breaker and put a clamp around the hot and neutral for the lighting circuit inside the panel. You should see no detectable current with the lights ON. There could still be a small leakage that trips a GFCI or AFCI, but it would show if the neutral had been miswired.