All AFCI breakers in a panel failing

[Sparky Adam]

I've run into this issue a couple times these past few months. The problem is that we are having all the AFCI breakers (both standard and combo) fail in an energized panel. The won't stay on and will immediately trip when reset. This has only happened on QO load centers with plug in neutrals.

Swapping in all new AFCI breakers is what got the panel working again.

Has anyone had this happen before and have any of those times led to a solution as to what may be causing this?

 

[electrofelon]

I recently had a client who fired up his backup generator and it had an open neutral. Fried a few things in the house and two AFCI's wouldnt reset, and one other has been problematic. You would probably have other symptoms if you had an open neutral though. Maybe a transient or surge? I think part of the justification for the surge protector requirement, besides square D pushing every cycle for a decade or two, was to keep the non working AFCI's "working".....

 

[Sparky Adam]

I don't think it was an open neutral, but I can't rule that out. This issue happened on a new home some time after the meter was set.

 

[kwired]

I think part of the justification for the surge protector requirement, besides square D pushing every cycle for a decade or two, was to keep the non working AFCI's "working".....

If they been replacing them under warranty sort of makes sense. Could also just refuse to warranty if not any surge protection present.

I still question whether these miracle fire prevention components will work when called upon in ~20 years when wiring conditions degrade enough that they possibly have some real justification to be there?

We are finally getting to that point where the earliest required AFCI's are getting to be that age - but at same time those weren't good enough and then came the combination type that would do what the first ones initially claimed they would do.

 

[mtnelect]

My experience with AFCI / GFCI is the neutrals. Each circuit has to be identified and isolated from the panel to the end of the circuit. This includes all the junction boxes. No shared neutrals !

 

[ActionDave]

My experience with AFCI / GFCI is the neutrals. Each circuit has to be identified and isolated from the panel to the end of the circuit. This includes all the junction boxes. No shared neutrals !

That would be true for any circuit.

 

[Sparky Adam]

If they been replacing them under warranty sort of makes sense. Could also just refuse to warranty if not any surge protection present.

I still question whether these miracle fire prevention components will work when called upon in ~20 years when wiring conditions degrade enough that they possibly have some real justification to be there?

We are finally getting to that point where the earliest required AFCI's are getting to be that age - but at same time those weren't good enough and then came the combination type that would do what the first ones initially claimed they would do.

Do you really think we'll see wire degradation in modern day wiring methods? I mean, opened up jboxes made up in the 40s with black steel conduit and cloth wiring that have had no issues since they were installed and were in pretty darn good shape even after having modern appliances used on them the last 20-30 years.

 

[mtnelect]

That would be true for any circuit.

Yes, that would be true if the installer followed those guidelines. But when you are experiencing AFCI / GFCI problems that is what you look first for ... neutral sharing.

 

[Fred B]

Yes, that would be true if the installer followed those guidelines. But when you are experiencing AFCI / GFCI problems that is what you look first for ... neutral sharing.

Issue sounds as if OP indicates the breakers originally functioned then shortly stop working. (Could be wrong, OP would need to clarify.) If that is true, neutral sharing not likely unless someone went into a jbox and made alterations after the fact. But, I've seen where a surge had taken out a bunch of them all at once. Fried the internal electronics. Given location I would think lightning strikes a very real possibility. This I believe also reasoning for inclusion in code to mandate whole house surge protection devices, the fryability of AFCI/GFCI breakers by surges.

If you're replacing them anyway and mfg not giving any warrenty, I would open one up to see condition of internal components looking for burnt circuit boards.

I've also witnessed where original GC that did installation did not adequately terminate the connections leaving them loose and that caused the AFCI to trip under load. Tightened to spec's and they no longer tripped. OP may have by trading out breakers, adjusted enough of the tightness so that the new ones didn't trip. (Just speculating.) Was it same builder for all the failing AFCI breakers that changeing the breakers fixed issue? I also believe reason behind making torquing with a "calibrates torque tool" required in the code now. 110.14(D) 2017 NEC

 

[Sea Nile]

...... all the AFCI breakers (both standard and combo) fail in an energized panel....... This has only happened on QO load centers with plug in neutrals.......Swapping in all new AFCI breakers is what got the panel working again...... what may be causing this?

This is just a theory... One breaker has a neutral to ground fault, and because it is on the 'plug on neutral bar', all of the other breakers are between or on the far side of the bad breakers neutral connection point and the main bonding jumper.

Of course I could be completely wrong, but that's the first thing I would check if I were trouble shooting based on the information provided.

 

[retirede]

Yes, that would be true if the installer followed those guidelines. But when you are experiencing AFCI / GFCI problems that is what you look first for ... neutral sharing.

For troubleshooting tripping issues, yes.

This thread is about the existing breakers all failing at once. Downstream neutral sharing is not going to cause this.

 

[Little Bill]

This is just a theory... One breaker has a neutral to ground fault, and because it is on the 'plug on neutral bar', all of the other breakers are between or on the far side of the bad breakers neutral connection point and the main bonding jumper.

Of course I could be completely wrong, but that's the first thing I would check if I were trouble shooting based on the information provided.

A plug on neutral bar would be no different than a screw type in that both would have continuity between all conductors on the bar. A ground to neutral fault on one line would not cause the others to trip.

 

[kwired]

Do you really think we'll see wire degradation in modern day wiring methods? I mean, opened up jboxes made up in the 40s with black steel conduit and cloth wiring that have had no issues since they were installed and were in pretty darn good shape even after having modern appliances used on them the last 20-30 years.

Do you not think there can be poor terminations that eventually fail or poorly protected cables that finally "wear through" from years of abuse? This is some of the types of things the AFCI was supposed to protect us from since they were first introduced.

I've come across many older generation GFCI's through the years that will no longer trip yet still pass power through them. Don't know if AFCI's have self testing logic in them or not, and they don't really tell us just exactly what pressing the test button does, it is a secret apparently, for all we know it may be some sort of simple shunt trip setup that tests nothing.

 

[kwired]

Yes, that would be true if the installer followed those guidelines. But when you are experiencing AFCI / GFCI problems that is what you look first for ... neutral sharing.

You are not likely to go months/years then all of a sudden have AFCI/GFCI problems because of mismatched neutrals, it will be a problem right after installation on GFCI's and for the most part will be a problem for any AFCI that still has 30mA GFP function incorporated into it as well. AFCI's that don't have the GFP shouldn't be effected as they don't necessarily even need a load side neutral to connect to them, just the line side neutral to power the logic board.

 

[kwired]

This is just a theory... One breaker has a neutral to ground fault, and because it is on the 'plug on neutral bar', all of the other breakers are between or on the far side of the bad breakers neutral connection point and the main bonding jumper.

Of course I could be completely wrong, but that's the first thing I would check if I were trouble shooting based on the information provided.

It is the same neutral "bus" for all them regardless if it is plug on neutral or using the terminal screws. Could even just have a wire for a bus and land each individual neutral via split bolt, compression terminal, etc. and you still have about same thing. Keep in mind there is only one common conductor back to the supply in any those setups. If you ran separate conductor for each circuit all the way to the source there is still only one neutral point to connect them to at the source.

 

[Sea Nile]

I was expecting push back on my theory. And of course I know all the neutrals are bonded to the ground at some point.

But there is a slight difference as to where they are connected in relation to the other breakers. As someone said, neutrals tied together down stream will not affect all the breakers. My theory is that on a "traditional" neutral bus, the point of connection is far enough away from the breakers that it won't affect the adjacent breakers. But on a plug on neutral system, the connection the breakers have to each other is closer than the connection to the enclosure and main bonding jumper. It's the only thing I can see that makes sense considering it only happens on plug on neutral.

 

[Little Bill]

It is the same neutral "bus" for all them regardless if it is plug on neutral or using the terminal screws. Could even just have a wire for a bus and land each individual neutral via split bolt, compression terminal, etc. and you still have about same thing. Keep in mind there is only one common conductor back to the supply in any those setups. If you ran separate conductor for each circuit all the way to the source there is still only one neutral point to connect them to at the source.

Now where have I heard that................maybe post #12?

 

[ramsy]

It's the only thing I can see that makes sense considering it only happens on plug on neutral.

You can prove it by disconnecting hot wire, and see if it trips, or use a GFCI breaker, as you swap it between different bus stabs.

 

[kwired]

I was expecting push back on my theory. And of course I know all the neutrals are bonded to the ground at some point.

But there is a slight difference as to where they are connected in relation to the other breakers. As someone said, neutrals tied together down stream will not affect all the breakers. My theory is that on a "traditional" neutral bus, the point of connection is far enough away from the breakers that it won't affect the adjacent breakers. But on a plug on neutral system, the connection the breakers have to each other is closer than the connection to the enclosure and main bonding jumper. It's the only thing I can see that makes sense considering it only happens on plug on neutral.

Outside of whether or not the plug on connection is compromised in some way, there is no difference. Homeline is what I am most familiar with, those plug onto same bus you would land the pigtail neutral on, Guessing many others are about the same. You could either use a plug on neutral breaker or use a pigtail neutral breaker and land the pigtail at nearly the same spot on the bus, will have to be just slightly to one side or the other of where the plug on lands but shouldn't really be any significance in location of that connection to the rest of the breaker.

And in these "loadcenters" the hot side plugs onto a bus in similar fashion as well even with the pigtail neutral breakers, why should that connection be any better or worse?

 

[Sea Nile]

Outside of whether or not the plug on connection is compromised in some way, there is no difference. Homeline is what I am most familiar with, those plug onto same bus you would land the pigtail neutral on, Guessing many others are about the same. You could either use a plug on neutral breaker or use a pigtail neutral breaker and land the pigtail at nearly the same spot on the bus, will have to be just slightly to one side or the other of where the plug on lands but shouldn't really be any significance in location of that connection to the rest of the breaker.

And in these "loadcenters" the hot side plugs onto a bus in similar fashion as well even with the pigtail neutral breakers, why should that connection be any better or worse?

I don't know, just a theory until someone tests it. I'm perfectly fine if my theory is wrong, it's just a product of a 1 minute brain storm.