The last week an electrical service person came to update the circuit breakers from regular to AFCI. But they could not find the root of the problem and they will come again in one week but I wanted to ask here for suggestions that maybe can help to that persons and avoid mistakes an check they make according the latest NEC.

With regular circuits there is no problem at all. Everything is working perfectly. Then what about they tested here are my questions:

1.-For example they replaced the kitchen circuit breaker to AFCI but making tests that persons they found that if you turn on any light or connect anything in any outlet and you turn on, then the foyer trips the new kitchen AFCI. The AFCI does not trip unless you turn on anything on foyer. 2.-They made the opposite test. Connect the AFCI to the foyer and a regular circuit breaker in the kitchen and the same if you turn on anything in the kitchen then that trips now the foyer. 3.-The same between the dinning room and the garage lights. After put any AFCI circuit breaker on any circuit then the regular circuit will trip the AFCI. Like point 1 but now between garage and dining room. 4.-About the living room is more complex maybe because if they connect an AFCI circuit breaker in living room it trips always it never turns on. They disconnected all neutrals from main box panel and also they switched off all breakers at home leaving just on the living rooms and it trips. In point 1,2 and 3 the AFCI turns on and give power to the correspondent section of the home and trips only when you turn on any light or anything in the section of the regular circuit breaker but here in point 4 in living room is different because the AFCI trips since the beginning and including like I mentioned before they switched off each breaker and dissconected all neutrals on the main box in other word all the home without electricity except the living room AFCI circuit and it trips always.

What could be the root of the problems? For example in point 1,2 and 3 could be a shared neutral problem? They made a suggestion that maybe this could be the problem and maybe this could be solved with a siemens q220afc 2 pole AFCI circuit breaker to use with shared neutrals or what I need to inspect or suggest to that persons now they come to check?

In point 4 is strange because it trips always and including being the only circuit alive in the test.

I hope someone can help to give me tips here to have knowledge and supervise these persons do the right thing.

Thank you

  • Has someone actually used the Siemens diagnostic tool on them to see why they're tripping? Nov 8, 2016 at 0:23
  • 1
    Two things could cause this: 1) There are mixed neutrals in junction boxes between separate circuits. 2) This one can be difficult to find.. because of the way AFCI breakers work, and how sensitive they are, simply having a neutral wire pressed too tightly to a ground wire will cause the breaker to trip. If you disconnect the neutral wires in the home run of the non-AFCI protected circuit that causes the trip, and the breaker holds, then you know the issue is more than likely the first one I listed. It sounds like that's probably the issue: mix-matched neutrals across your circuits.
    – Tyeler
    Nov 8, 2016 at 16:37
  • Thank you I will tell to the persons to make the tests. I saw they used extech gfci and afci testers and they saw only turning lights on and off and the circuit breakers tripped in less than one second there is no delay.
    – coerrace
    Nov 9, 2016 at 2:59


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