All Dual Function (AFCI/GFCI) Breakers Tripping

[WillLloyd]

We built a new home and installed two Square D QO panels with plug on neutrals. One is fed by a whole house gen/ATS, the other directly from the utility. Both panels have a mix of dual function, AFCI only, and thermal magnetic breakers. Most all circuits are on the dual function breakers, only a few are AFCI or thermal magnetic. Each panel has a plug in Square D transient protector.

On the first occasion, before there were any AFCI breakers in the panels, ALL the dual function breakers tripped (both panels). None of the thermal magnetic breakers tripped. Once this occurred, we added AFCI breakers to the frig and generator battery charging circuits. I called the utility company after this happened and they told me they had an issue but did not elaborate.

On the second occasion, about 6-months after the first occasion, all dual function breakers tripped (both panels). None of the AFCI or thermal magnetic breakers tripped. This trip occurred during a storm which resulted in a utility outage of several days.

We have had no other tripping issues.

I'm convinced these trips are utility related but I was hoping others can confirm or share thoughts on other possible causes.

Thanks in advance.

 

[gar]

180309-2431 EST

I assume you are an electrical engineer from your profile. So this thread probably won't be closed.

I have not kept up with new breakers.

I assume by thermal-magnetic you mean an original ordinary QO breaker that uses a U shaped bimetal strip actuator that performs both functions. Magnetic trip on high current, and thermal on low overloads.

What is a dual function, and what is an AFCI only? Title information should also go into the body of your post. Now I see dual function means AFCI/GFCI.

I would assume any breaker would have to have a normal trip characteristic. This could be done by keeping the normal thermal-magnetic trip actuator, and adding additional mechanism for electronic trip functions. Or everything could be done electronically. I would favor retaining the thermal-magnetic function. Proven reliability over a very long time frame. The last I was involved with design or problems in making breakers was in the early 1960s.

Usual transient voltage limiters are MOVs and do not have a very square limiting characteristic. These also fail on overload, too much heat.

What is a dual function breaker?

On the first occasion, before there were any AFCI breakers in the panels, ALL the dual function breakers tripped (both panels). None of the thermal magnetic breakers tripped.

I will assume dual function means there is some electronics. My guess a very large voltage spike is what tripped the electronic circuits.

If you have a power outage, of any obvious duration. turn off your main breaker until you know power has truly been successfully restored.

On the second occasion, about 6-months after the first occasion, all dual function breakers tripped (both panels). None of the AFCI or thermal magnetic breakers tripped. This trip occurred during a storm which resulted in a utility outage of several days.

Did tripping occur at the outage start, or when restored. Design of the electronic circuits may be the reason for the difference in tripping between AFCI and dual function.

.

 

[ramsy]

Handheld radios have been demonstrated to trip GFCI’s in close proximity.

Perhaps during POCO power outage or surges, GFCI breakers can be exposed to higher magnitudes of similar radio noise, without the benefit of branch-circuit impedance ahead of most outlet GFCI’s.

 

[GoldDigger]

Moderator Note: Will is in a peripherally related occupation, and although his question is not work related, it is also not asking for DIY advice on an electrical problem, but rather an attempt to understand the underlying phenomena. This is within normal Forum scope and the thread will stay open unless it ventures into Will actually interacting with the wiring himself beyond what any homeowner would normally do.

 

[romex jockey]

an afci is 30ma, a DF is 5 ma

that's the only real dif

~RJ~

 

[WillLloyd]

Thanks for the replies. I'm just trying to confirm (hoping) that the trips are due to transients that occurred on the utility side and not from an issue within our house. We are in the middle of the woods so no radios nearby.

We have not moved in yet but I assume the trips occurred at the beginning of the outage, not when power was restored. I'm pretty sure of this since we tested the gen/ats and never had a problem with the breakers tripping.

If it helps, AFCI breakers are QO120PCAFI; dual function breakers are QO120PDFC; and the others are standard 2-pole QO breakers.

In conversation with a friend of mine, a very practical EE, we think transients during the outage is causing the GFCI to see an imbalance from the line side long enough to cause them to trip. I was hoping others have seen this so I can go back to finish building the garage......

 

[gar]

180310-0749 EST

WillLoyd:

An MOV or similar transient limiter does not have any affect on the rate of rise of a transient until it starts to clip the magnitude of the pulse.

Peak clipping voltage will be a function of the power line source impedance, and the MOV characteristics.

RF triggering is not likely (nearly impossible) unless AC power is present at the time of triggering.

I suspect PC board layout with too long of an unprotected lead to the SCR gate could be the cause of the difference between the breakers. Power has to be present at the time of tripping. A resistor in series to the SCR gate and directly at the gate, and possibly a small capacitor from gate to cathode of the SCR directly at the SCR might prevent this problem. Unprotected means something to minimize capacitive coupling to the gate.

.

 

[ptonsparky]

The posts and threads on random AFCI/GFCI trips lately have dealt mostly with SQ D QO breakers, or it appears to me that is the case. Could be just the amount of them being used versus others.

GFCIs are looking for an imbalance on the load side, not the line. AFCIs are supposed to be looking at the load as well but while MFGs may deny they have a problem, we in the field don’t really know what the heck they respond to. Could be the energizer bunny.

These breakers now have on board diagnostic that indicate why they last tripped. Have you looked at that code?

 

[don_resqcapt19]

an afci is 30ma, a DF is 5 ma

that's the only real dif

~RJ~

At least two brands of AFCIs no longer have a ground fault detection in their AFCIs.

Edit...sorry this does not really apply. I missed the title of the thread.

 

[gar]

180310-1315 EST

A long time back I presented some information on a duplex GFCI. See http://beta-a2.com/GFCI.html and photo next to last. I failed to index P# after 5. So there are many 5s. Here you see a long trace from an 8 lead IC, pin 1 bottom left corner of IC, down to the mid terminal of a component, SCR, near lower edge of board. The SCR is on the other side of the board. All you see on this side are the three dots the SCR is soldered to.

See http://www.idea2ic.com/GFI/LM1851.pdf for a likely diagram of the IC. Note pin 1 is trigger to SCR.

This long lead to the SCR gate provides a way for stray transients to capacitively couple to the SCR gate. The capacitor C2 is in the totally wrong place, and there should be a series resistor in that trace.

.

 

[kwired]

Been a few years ago, but I was working in a new home we were about done with, AFCI's were already installed and operating, back when we only had to use them for bedrooms. This was a house out in country on rural distribution system. One day the power "blinked", presume something happened that caused a circuit recloser to cycle. I noticed not everything came back on - went to the panel and some but not all the AFCI's were tripped. I never figured out exactly what happened and never got any service calls on those either after owners moved in. Still think maybe some sort of transient effected them or even inductive kickback from somewhere. Seems possible the breakers that did trip were the ones with a load on them -but don't know for certain. Those would have been QO breakers, combination type AFCI but was long enough ago I don't think they would have had the test feature to tell what made it trip.

 

[hbiss]

I'm assuming that you don't have any kind of surge suppression devices on those circuits. Power strips, plug-in surge suppressors or anything with a built-in power line surge suppressor will trip GFCI receptacles and breakers anytime a transient comes along from the POCO. As a practical matter you can't use surge suppression devices with GFCIs.

-Hal

 

[kwired]

I'm assuming that you don't have any kind of surge suppression devices on those circuits. Power strips, plug-in surge suppressors or anything with a built-in power line surge suppressor will trip GFCI receptacles and breakers anytime a transient comes along from the POCO. As a practical matter you can't use surge suppression devices with GFCIs.

-Hal

Many items with electronics in them possibly have some level of surge protection within as well often right at the front end of any internal AC-DC power supply.

 

[ramsy]

..Power strips, plug-in surge suppressors or anything with a built-in power line surge suppressor will trip GFCI receptacles and breakers anytime a transient comes along from the POCO. As a practical matter you can't use surge suppression devices with GFCIs.

Good point, with very few exceptions;
1) Fuse Box surge protector - shunting ahead of GFCI's, to Main Bonding
2) Surge protect certain AFCI outlets, that only use GE Arc-Fault breakers
3) Two-wire surge protectors - shunting to Neutral - if such animal exists?

 

[WillLloyd]

So Gar, I think you are saying that the duplex type GFCI's can allow transients to couple and cause a trip. Since ours are panel breakers there is a possibility that we are seeing the same thing. Makes sense since all of them trip.

Kwired, I was hoping someone else would have seen this too. We are also at the end of a rural distribution system. Since we dont live there yet, few of the breakers have any load on them but they all tripped.

Re surge suppression - we only have the protector in the panel itself. Nothing connected downstream of breakers. Still may be worth a conversation with Square D about this setup.

Thanks all for the input. I think I'm going to try to get ahold of someone at Square D that I can have a conversation with. Over time I will have to replace the breakers if we need generator power to that circuit. Doesn't do us any good to have a generator if all the panel board breakers are tripped and we are not home to reset.

 

[ptonsparky]

So Gar, I think you are saying that the duplex type GFCI's can allow transients to couple and cause a trip. Since ours are panel breakers there is a possibility that we are seeing the same thing. Makes sense since all of them trip.

Kwired, I was hoping someone else would have seen this too. We are also at the end of a rural distribution system. Since we dont live there yet, few of the breakers have any load on them but they all tripped.

Re surge suppression - we only have the protector in the panel itself. Nothing connected downstream of breakers. Still may be worth a conversation with Square D about this setup.

Thanks all for the input. I think I'm going to try to get ahold of someone at Square D that I can have a conversation with. Over time I will have to replace the breakers if we need generator power to that circuit. Doesn't do us any good to have a generator if all the panel board breakers are tripped and we are not home to reset.

I can almost hear it now.

Let us know if you find out anything new.

 

[romex jockey]

At least two brands of AFCIs no longer have a ground fault detection in their AFCIs.

Edit...sorry this does not really apply. I missed the title of the thread.

Yes it does Don

I switched to GE & use a lot of DF's

Almost zero callbacks vs. my past Siemens & Sq D's

they also can 'share' a neutral

Just what is different ,i can't say

But i had eaten enough 'call backs' to say i'm glad i switched

~RJ~

 

[kwired]

Yes it does Don

I switched to GE & use a lot of DF's

Almost zero callbacks vs. my past Siemens & Sq D's

they also can 'share' a neutral

Just what is different ,i can't say

But i had eaten enough 'call backs' to say i'm glad i switched

~RJ~

A dual function breaker is one with both GFCI and AFCI function.

GE might have AFCI only breakers that don't need a neutral, but all GFCI's need a neutral and can not share a neutral with another circuit. I am not familiar with GE's AFCI line -don't even know if I have ever seen one other then on the shelf at big box store (GE just not that popular here on new residential construction) but their DF breakers have to use a neutral to have proper function of the GFCI component.

 

[hbiss]

Thanks all for the input. I think I'm going to try to get ahold of someone at Square D that I can have a conversation with. Over time I will have to replace the breakers if we need generator power to that circuit. Doesn't do us any good to have a generator if all the panel board breakers are tripped and we are not home to reset.

I want to hear that conversation too because I'm sure they are ready for it- if they will even talk to you. If you search this forum the consensus of opinion is that AFCI is one of the biggest frauds on the American public in a long time. About the only thing they are good for is nuisance tripping.

As professionals we can't recommend that you replace them with regular breakers for liability reasons. I'll leave it at that.

-Hal

 

[ramsy]

..If you search this forum the consensus of opinion is that AFCI is one of the biggest frauds on the American public ..

With a bit of caution relying on anecdotal surveys and internet opinion of course.

Further, not all experience with AFCI’s are published here, including mine, which has been amazement of how well they work when grabbing a loose plug with sparks.

For my service work, AFCI code has been an effective barrier to entry against unqualified persons monkeying with my clients property.