AFCI Madness - help!

[GoldDigger]

We had problems like that years ago on some new track homes years ago, if you know were the home run is you can try switching the neutral and hot wire at the panel and first outlet, it worked the few times we had tripping AFCI

A very interesting trick!
Presumably you do that so that the errant screw goes through the neutral instead of the hot?
If the problem is in fact an EGC to neutral connection you will certainly find it or burn it out! :angel:
Does the NEC allow you to do that with NM or wire even if you phase tape all four ends?

 

[norcal]

Was the jury rigging done by removing the load neutral from the AFCI, & landing it on the neutral bar + disconnecting the AFCI neutral pigtail & insulating it, so it functions as a circuit breaker only? That stunt is pretty easy to spot in a open panel.

 

[Coppersmith]

The arc signature detection for series arcs cannot be activated until the instantaneous current exceeds about 7A, to reduce the likelihood of false tripping from noise from other circuits or sources.
That is why I asked what the load current was when you saw it trip.

If you know that the home run goes to a switch box or a receptacle then you could temp wire a receptacle and place a load on the home run. I have a large drill motor is use for such things.

The load that tripped it was a 25 watt incandescent light bulb so not even close to 7 amps. I didn't know there was any kind of ground fault sensing in those things. Thanks for the info.

 

[Coppersmith]

If you look at page 3 of this PDF, you will see a detailed description of how to determine the cause of a trip.

This seems weird:

To reset Fault Indication:
• Perform the CAFI Fault Indication Procedure a total of 6 times
• Verify by performing CAFI Fault Indication Procedure with a trip at 5.0 seconds(Procedure Complete) result.
• An automatic reset of Fault Indication will occur if the CAFI circuit breaker has been powered continuously for 27 days.

 

[Coppersmith]

Was the jury rigging done by removing the load neutral from the AFCI, & landing it on the neutral bar + disconnecting the AFCI neutral pigtail & insulating it, so it functions as a circuit breaker only? That stunt is pretty easy to spot in a open panel.

I don't know what was done. I was called in after the home inspector spotted it and the handyman fixed it.

 

[GoldDigger]

This seems weird:

To reset Fault Indication:
• Perform the CAFI Fault Indication Procedure a total of 6 times
• Verify by performing CAFI Fault Indication Procedure with a trip at 5.0 seconds(Procedure Complete) result.
• An automatic reset of Fault Indication will occur if the CAFI circuit breaker has been powered continuously for 27 days.

It makes sense to me as follows:
If, for example, a GF causes a trip when first activated and you correct the ground fault, and a day or two later a momentary short in equipment causes a trip. You do not the GF indication to stick around to confuse the diagnosis of the new trip.

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[iwire64]

Separate your neutrals.

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[Coppersmith]

Thank you everyone for your help. I have learned much about AFCI's in this thread. Unfortunately, the homeowner got impatient and hired another electrician to complete the job. I was told he found two wires arcing in a fan downline of the switchbox where the HR comes in. This doesn't make sense to me since after I opened the switchbox and disconnected all the loads the AFCI was still tripping, but whatever. Truthfully, I glad to be rid of this headache of a problem. I got paid for the work I did. Thanks to your help I now have a few more bullets in my troubleshooting gun for next time. (However if someone calls and says "AFCI trouble" to me, I might be too busy to help. )