AFCI Tripping

[thedude]

I have 2 AFCI's that serve three upstairs bedrooms. The AFCI's will test fine at the panel, and will stay switched in when reset (I have checked voltage at the receptacles, looks good). The problem occurs when I plug in a lamp or other device into any of the bedroom receptacles. Each AFCI will trip (independant of one another) when a device is plugged into a receptacle on the circuit. A digital clock will not trip wither AFCI (perhaps not enough draw?). I switched out AFCI's and still the same problem. I wired my kitchen plugs into the AFCI's and they work fine, no trip when plugging in any device. Wondering if the problem could be shared neutral between both bedroom receptacle circuits? To be clear, the AFCI's serving the bedrooms will stay switched in until a device is plugged into any bedroom outlet.

Thanks in advance for any advice.

 

[iwire]

Wondering if the problem could be shared neutral between both bedroom receptacle circuits?

In my opinion you definitely have an issue with a neutral touching ground or cross connected between them.

If when you say a ''shared Neural" you mean a 3 wire cable is the home run from the panel to the outlets and your using single pole AFCIs it will never work.

 

[mdshunk]

I concurr.

If this is a 3-wire circuit, you need a 2 pole independant trip AFCI breaker. It's also possible that if you retrofit these AFCI's in an existing home, you may have a neutral and ground touching in a box someplace from the original install. Taking the neutral and ground for that circuit off the bars in the panel and checking them with an ohm meter is the typical first step to check into that.

 

[andinator]

If there is a shared neutral, either by design (mwbc) or on accident (two seperate neutrals tied together in a box) shouldn't the AFCI trip without any load? Why is it holding closed with no load??

 

[iwire]

Why is it holding closed with no load??

The reason the AFCI is tripping is because along with looking for arcs it also looks for ground faults. It senses a ground fault by looking for a current imbalance on the circuit conductors.

With no load there is no current at all, without any current there is no imbalance. Once you add a load there is current and ground faults can be detected.

 

[thedude]

AFCI's tripping

AFCI's tripping

Tested the netrual to ground on both circuits for continuity. Guess what...I've found the problem. I guess the next step is pulling every receptacle and taking a look.

thanks for the help guys.