The AFCI breakers that govern the bedrooms in my house occasionally nuisance-trip, and I'm pretty sure that we don't have anything bad plugged into them. I'd like to replace the breakers with new ones, just to be sure that the problem isn't the breakers.

Google is good at giving me the information on how to do the replacement. The hardware store down the street has the exact same model of AFCI breaker, which is this one.

However, I notice one thing that's different, and I'm having trouble getting Google to give me a clear answer on this one. On my breakers, in very fine print on the label, under the letters "AFCI", there is small text saying "10kA". The ones at the hardware store, pictured at the URL linked above, say "22kA" in the same spot.

Is that the "trip" rating for the AFCI portion of the breaker? If so, does that mean that 22 is harder to trip than 10? If so, then wouldn't I *want* the 22 so that it doesn't nuisance-trip as often?

Looks like, yes, the 22kA vs 10kA is in fact the interrupt rating.

My remaining questions are:
- 22 is harder to trip than 10, right? Thus the 22 would nuisance-trip less often, right?
- By replacing a 10 with a 22, would I be violating code or something?

Isn't the 10kA or 22kA (both of which sound like a sod of a lot) the maximum value the breaker is able to interrupt? i.e. if your circuit suddenly fails and draws 15kA, the 10kA breaker will try to trip but fail to do so. If that is the case then the 22kA would be strictly safer than the 10kA, so replacing the 10kA with the 22kA would seem unlikely to affect compliance.

Peter

Shouldn't make a difference - what trips the breaker is current above the 15A fuse rating. IIRC the interrupt rating comes into play when you have a major short circuit; a major short could fuse the contact elements together - not separating and breaking the current. The 22kA (22.000 Ampere) is simply better at breaking the current in a major short situation. Should be OK by code, but IANAE...

A new breaker might nuisance break less simply by being new and unworn...

Oh! That makes more sense. Thank you Michael and Peter.

Next question:

Internet video shows a guy replacing an old style breaker, the one with just a hot wire but no neutral wires, without turning off the whole house main breaker.

Would I be able to get away with the same thing with an AFCI breaker, or must I shut down the whole house to change out an AFCI breaker?

Please don't DIY this if you're asking this sort of question.

Indeed.

An open electrical panel, while live, has serious potential to hurt you if you do not know what you are doing, or do not it correctly, without error.

What michael describes is the current limiting function of your afci breaker. It also detects arc faults which can cause fires while staying under the mag trip limit. These are separate functions.

I doubt the 22ka and 10ka ratings will make much difference to your problem. You've probably either got a pos breaker or a noisy dimmer or an actual arc fault.

The first thing to do is to replace your afci (and having an afci (as well as a gfci) is a good idea) with a Square-D brand breaker. These are the best and will not nuisance trip. I've found that Eaton and GE (both common in houses because they be cheap) do nuisance trip.

Once you have the SqD breaker in place, and if it still trips, it may be an electrically noisy light dimmer (they tend to look like arcs to the afci anyway), or you may have a loose connection, corroded switch, or some other actual arc fault to track down.

And definitely get someone to do this for you. On a house load center, even with the main breaker off, there will still be power available to kill you.

Well I went ahead and did it myself, and it turned out to be pretty easy.

I did in fact shut down the whole house before doing it, and I'm still alive to type this so all is well.

I replaced the AFCI breakers with a different brand than the one that was installed there. The one that was installed was Siemens, and the only other brand they had at the store was GE. So if you say GE tends to nuisance-trip as well, I could be in the same boat. I can mail-order some Square-D breakers if these keep tripping.

Note that there are no dimmers on these circuits, and the only thing that's ever turned on on those circuits when they trip are incandescent 60-watt light bulbs.

Home Despot carries Square-D. Siemens is a pretty good brand for their other equipment, I've never used their breakers.

A loose wire on those incandescent sockets would cause this.

It is an easy job. Glad you're still alive!

You know, I would say that it was caused by a loose wire or some other genuine issue, except, there are four Siemens AFCI breakers in our panel and we've had each one of them randomly nuisance trip at different times. That there tells me it's crappy breakers rather than a wiring issue.

Thanks everyone for all your excellent advice on this thread.

So, Siemens bought up the old Murray brand, that circuit breaker is actually a Murray. They are known for being the cheapest.

Interesting.

It's funny, my house is nearby both a Home Despot and a Low's. I usually go to the Low's, so if I'd changed my pattern and went to HD instead, I probably would have come home with the Square-D breakers. But since I didn't, my replacements are GE breakers, I'm worried about them still tripping.

Return policy?

I don't know about Lowe's, but I love Home Depot's return policy. They'll take pretty much everything back, even if you use it.