[paulgarett]

I installed AFCI breakers for all circuits in a new sub panel, except the dryer, oven, and a sub-feeder breaker. Three of the AFCI breakers kept tripping or tripped after a few minutes. The wiring in the house, in general, was not done properly, by the previous electrician or home owner.

Do AFCI breakers trip if neutrals are shared by other circuits in a junction box?
This is what i suspect is the problem.

What are other possible causes of AFCI tripping, besides the obvious, arcing?

Is there a tool available that checks individual circuits for faulty wiring or shared neutrals?

 

[Ultrafault]

In my experience neutral faults and shared neutral will cause afci trips.

 

[papaotis]

10-4! it says that right in the manual, no shared nuetrals!:whistling2:

 

[Ultrafault]

10-4! it says that right in the manual, no shared nuetrals!:whistling2:

Holy cow things have manuals?!?!

 

[The_Modifier]

I have heard good reviews of this tool HERE

But I have also found that if the ground wire in receptacles touches the neutral it will cause trips as well.

 

[don_resqcapt19]

Most AFCIs have ground fault protection at ~30mA so if you have a neutral to ground fault or shared neutrals, they will trip.

 

[MTW]

Most AFCIs have ground fault protection at ~30mA so if you have a neutral to ground fault or shared neutrals, they will trip.

I thought the new combo AFCI's don't have it?

 

[macmikeman]

I thought the new combo AFCI's don't have it?

Sure they do. Touch a neutral to the ground wire when the breaker is on to test this out.

 

[macmikeman]

My personal belief (well.........) is that gfi is still the major functioning component in them other than the plain old short circuit and overload functions we had in breakers for the last 45 years...

 

[don_resqcapt19]

I thought the new combo AFCI's don't have it?

As far as I know, the only manufacturer that has removed the most important part of the AFCI (my opinion is that the GFP is the most effective part) is GE.

 

[MTW]

As far as I know, the only manufacturer that has removed the most important part of the AFCI (my opinion is that the GFP is the most effective part) is GE.

Right, that explains why you can install GE AFCI's on MWBC's.

 

[USMC240]

I ran into the exact same issue last week. If it seems to reset then trips as soon as a load is applied it's probably a shared neutral. There is also a very simple built-in diagnostic you can run on at least some afci's that will tell you if it is experiencing an arc-fault or a ground fault although I suspect that the incidence of arc faults is very low.

After about 6 hours of searching we finally disconnected an old smoke detector on the circuit and the problem was resolved. It was a huge pain.

 

[paulgarett]

How does this tool work. I looked it up but the info does not explain how it works.
It is an expensive tool that could possibly save a lot of time and make customers happy. But is it worth it? Do you have any experience with this tool?

 

[aftershockews]

How does this tool work. I looked it up but the info does not explain how it works.
It is an expensive tool that could possibly save a lot of time and make customers happy. But is it worth it? Do you have any experience with this tool?

 

[chicken steve]

Amazing device that can distinguish between normal switch and/or external device arcs signatures like vacuum motors , and that which is it quantifies as an arc of detrimental character

Of course, it fails to explain HOW this diagnostic marvel is able to come to this conclusion.....

~CS~

 

[HARRY304E]

I installed AFCI breakers for all circuits in a new sub panel, except the dryer, oven, and a sub-feeder breaker. Three of the AFCI breakers kept tripping or tripped after a few minutes. The wiring in the house, in general, was not done properly, by the previous electrician or home owner.

Do AFCI breakers trip if neutrals are shared by other circuits in a junction box?
This is what i suspect is the problem.

What are other possible causes of AFCI tripping, besides the obvious, arcing?

Is there a tool available that checks individual circuits for faulty wiring or shared neutrals?

Such things like neutrals mixed together from different circuits in switch boxes will also cause tripping.


Ground wires touching the neutrals in any box will also cause tripping.

Loosely spliced splices caused by not twisting your splices together first and checking them to make sure they're good before putting on your wirenuts will cause tripping.

Connections to devises , check them and make sure that everything is tight before putting them in the box making sure the ground wire does not touch other wires or even the device it's self.

 

[chicken steve]

Think gfci to TS an afci imho....

~CS~

 

[paulgarett]

Nice tool. Thanks for the information.