Now, Square D Combo AFCI Breaker Trips Opens w/No Load Side Connections QO120CAFI

mysterylectric

Hi,

I have a Square D QO120CAFI issue DP-3640 combination AFCI circuit breaker. Basically I bought it to see for myself if these functioned as advertised. It is in a subpanel that supplies the kitchen.

It seemed just fine for about a month, maybe two.

Then it tripped one day. I don't think it was precipitated by an obvious event on the circuit. On the other hand, I think I was in the kitchen (w/the panel) at the time it happened, probably using one or more appliances and perhaps unplugging/plugging something in.

A persistent fault seemed unlikely so I reset the breaker. It popped open right away.

Unplugged all appliances from circuit, still popped.

Shut off breakers to all other kitchen loads. Ditto

I probably disconnected the load side hot wire first. Still popped upon reset.

Then I probably disconnected load side neutral. Still popped.

Tossed the breaker aside for further investigation.

Today I put the breaker back into the panel and tied it to the neutral bar. Still trips, with no load side connections.

It won't trip with the breaker's neutral disconnected, of course.

I've read about the importance of making sure to reset these properly, ie: with gusto. No help.

It seems very unlikely to me that it is "nuisance tripping" in the traditional sense, ie: that the simple fact that there are no load side connections is causing a nuisance trip

It's probably about %80 certain I energized it without any load side connections when I first installed it, it never tripped during or after installation, except on hitting the test button.

So this breaker either suffered infant mortality or was destroyed by a common fault.

How common is this experience?

And, what's the fastest way to get a replacement from Schneider? Assuming things don't work out with the retailer (though I tend to think they will exchange it no questions asked).

-Jeff

kbsparky

Bad breaker. Take it back to the store, and ask for a replacement.

This type of thing happens all the time, and across all brands.

This is one reason why I do not believe that AFCI breakers are ready for prime time: They have been added into the Code as a result of extensive lobbying efforts from the manufacturers. The public has become the guinea pigs and beta testers of these.

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Leah Frances

I've had one of these bad out of the box. Took it back, next one worked.

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If I could only remember to THINK about what I was doing before I did it.

mysterylectric

Are these types of problems far more common with CAFI breakers? Far more even than for GFI? In theory I can see how a GFI could use as few as zero semiconductor components, at most some analog. CAFI's I's think really need microprocessors.

Yeah, from the beginning I saw this as a very difficult engineering task and noticed far more talk about why it's such a wonderful idea than talk about reliability or whether they currently work as intended. I bet a lot of homeowners will be replacing these themselves, with exact replacements or the standard equivalent. That's a lot of untrained fingers in a lot of boxes across the country.

frenchelectrican

I do know for the fact with early series of AFCI breakers they were kinda major pain in the back end and I have ran into that more than once when I did the service call.

Basically what I do is do a basic troubleshooting to make sure the neutal is not touching the ground conductor after that I go next step is get a GFCI breaker to test fire it to see if that hold if the GFCI breaker trip then you have grounding issue but if hold then I will dig deeper to find out the curpit.

For our Europeans side we do not have AFCI at all for now but not too far in future we will get something simauir what the North Américians have now.

Merci,
Marc

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The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )

jerryk1234

My new house ( built in 2008 ) has FOUR of these @#$@#$ things. They trip randomly. Sometimes, all four of them trip. Often when nobody's at home. It's a Square-D panel, I don't know the exact model# of the AFCI's.

My computers do NOT like having their power suddenly removed. OK, I put them on UPSs. OTOH, I do NOT like being woken up in the middle of the night by beeping UPS's.

Have AFCI's gotten any better in the four years since my house was built?

- JerryK

Billy_Bob

I recently read that radio frequencies from "Smart Electric Meters" can trip AFCI's!

Possible explanation to all these false trips? Maybe other RF too?

Here is a bit on that...
http://www.nachi.org/forum/f71/smart...g-afcis-65449/

jerryk1234

**** Ouch! That could indeed explain it. The combo AFCIs are quite complex, and probably have a microprocessor. If I buy a new one to try out, I might tear the old one apart, just for yuks.

- JerryK

kbsparky

Your surge units can trip out AFCI and GFCI devices by doing what they were designed to do.

Too bad the Code does not allow exceptions for such things these days ...

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