arc fault nightmare

[JTL ELECTRIC]

New construction that has two arc fault circuits feeding two bedrooms. The weird thing is that a study is also wired in with the two circuits, whereas the receptacles are on one of the circuits and the lights of the study are on the other circuit. The owner has not had issues with the circuit breakers tripping until she had a camera installed that had a transformer plugged into the wall receptacle of the study.

I was called in to verify that it was not due to the transformer, as I contract for the distributor of the camera company. I unplugged the transformer and the breakers continued to trip. After waiting for 15 min the circuit breakers held and life was good, so I thought. Without the transformer plugged in the breakers tripped again, so I replaced the arc fault breakers, thinking that they were defective.

This has had me scratching my head for the past week, please help

Joe:?

 

[kwired]

Make sure installation of the cameras did not create an intermittent fault in wiring (maybe a concealed cable was drilled into?)

Look for neutral to ground faults - may need a megger to detect whatever fault may be occurring.

There could be some other load causing the problem and it just seemed to coincidentally start happening when the camera was installed, so make sure to check other loads out.

 

[CONDUIT]

I have had some nuisance tripping before. Ended up changing out breaker and it took care of problem. You do need to verify that there are not any other issues that are causing it to trip.

 

[tek9]

What ive learned of this stuff,check for a nail or something like that nicking the insulation between ground and neutral,if the transformer thing does not contain a 50hz but a switch mode power supply,they often put harmonics back into the mains due to the crappy chinese electros used,these can cause an arc,bang breaker trips.