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William
Re: Circuit Breaker Types
sparky1 wrote:

just a way for certin companies to make more money.

That's what people said about regular circuit breakers when they first came out. I have no reason to doubt that AFCI breakers do exactly what they say they do. It's time that circuit breakers caught up with modern technology. I just wish they were more reasonably priced. Home Depot had some last month that were around 15 bucks, so maybe pricing is starting to come down on them.

Fencepost
Re: Circuit Breaker Types
MyMilan wrote:

It's time that circuit breakers caught up with modern technology.

The OP mentioned that one particular brand of AFCI had reports of a lot of nuisance tripping.

Not sure how it is with AFCI, but with GFCI it's a common problem on stages that older guitar amps will trip a GFCI because of stray voltage leakage. In some cases, these amps were just poorly designed -- even when "factory new" they exhibited leakage. In other cases, insulation on some of the components can deteriorate. This isn't really nuisance tripping, as it's really highlighting a problem with the equipment you didn't know was there.

On the other hand, an amplifier that is well-insulated and working properly (no leakage) can trip a GFCI when it is turned on, as the charging of capacitors can result in an imbalance between the legs of the circuit thereby tripping the GFCI. (If the amplifier is constructed with an isolating transformer, this shouldn't happen. Not all are.)

Even with regular breakers, you can have nuisance tripping with certain motor loads. For example, some 1 HP motors -- which have a theoretical running current of about 745 watts, or about 6 amps on a 120V circuit -- can exceed 15 amps at startup (depending on application). An improperly spec'd breaker could trip when this motor starts, especially if there are other loads on the circuit. I have experienced this many times when using my portable power miter saw.

What I wonder about is if an old motor with arcing brushes will trip an AFCI. How about a welder? How about a light switch that arcs when actuated?

My point is that what appears to be nuisance tripping may indeed be an indication of a problem you're not aware of. It may be that the device you are using is designed to have operating parameters outside the operating parameters of the circuit breaker. Before declaring a circuit breaker bad, whether it's a standard breaker, a GFCI, or an AFCI, first eliminate all possible problems and fix them. If you're still tripping, try to identify anything that could be operating normally yet still causing the tripping, and consider a different breaker designed to protect that load without tripping.

Back to MyMilan's post, it would be nice if tools and appliances would be designed properly so they wouldn't cause nuisance tripping of circuit breakers.

And yes, sometimes breakers do go bad. I had a breaker for a water heater go bad; it would randomly trip. Replacing the breaker resolved the issue.

And while I'm sure most everyone who's already posted in this thread knows this, never install a breaker or a fuse with an amp rating greater than what the smallest-gauge wire in the circuit is rated for.

William
Re: Circuit Breaker Types
Fencepost wrote:

Before declaring a circuit breaker bad, whether it's a standard breaker, a GFCI, or an AFCI, first eliminate all possible problems and fix them

I understand what you're saying, but in this case (with the square D AFCI) it appears it was the breakers fault. While researching AFCI breakers I remember running across a recall for them. Also, some people having issues with the square D brand of AFCI breakers replaced them with other brands - and guess what, the nuisance tripping all went away. It appears that the square D AFCI breakers were just poorly designed. There have even been people on this forum complaining about them. I was also told that Home Depot received so many complaints about them that they don't even sell them anymore. I don't know if they've been redesigned or not. In any case I'm just glad that I don't have to use square D AFCI breakers in my square D panel :)

dj1
Re: Circuit Breaker Types
MyMilan wrote:

I understand what you're saying, but in this case (with the square D AFCI) it appears it was the breakers fault. While researching AFCI breakers I remember running across a recall for them. Also, some people having issues with the square D brand of AFCI breakers replaced them with other brands - and guess what, the nuisance tripping all went away. It appears that the square D AFCI breakers were just poorly designed. There have even been people on this forum complaining about them. I was also told that Home Depot received so many complaints about them that they don't even sell them anymore. I don't know if they've been redesigned or not. In any case I'm just glad that I don't have to use square D AFCI breakers in my square D panel :)

I agree - Sq D AFCIs are not good, at least the ones I had the pleasure to use...

Fencepost
Re: Circuit Breaker Types

I think this article would be relevant to the discussion:

AFCIs Come of Age | The ASHI Reporter (October 2012)

Quote:

In November 2004, Square D announced a recall of 700,000 of its AFCIs. A malfunction in their test button could fail to activate the AFCI circuitry. As a result, the breakers would act like nothing more than (much cheaper) non-AFCI breakers. The recalled breakers had a blue test button. Square D changed the color of the test button in subsequent breakers. The breakers in the recall were branch/feeder types that do not meet present code.

Re: Circuit Breaker Types

AFCI breakers contain sophisticated computer chips and programs to respond to fire or safety issues. All are proprietary and achieve the objectives any way they choose. The ones I’ve studied don’t trip due to random sparks caused by arching brushes, single spikes, switching, etc.

In fact there are demonstrations that show some don’t detect the dangers of “glowing connections” which could result from loose wire nuts. Unfortunately,this is the type of fault that causes most fires.

Most respond to 30 milliamps of ground fault which would classify them as GFP breakers and could protect equipment. A Class “A” ground fault interrupter trips at no more than 6 ma. to protect personnel . Most trips are caused because of improperly wire branch circuits where the white wire touches the bare. Prior to GFCI and AFCI breakers this dangerous wiring error usually went undetected.

Early AFCI breakers were very troublesome but most problems have been corrected and now we should see electrically related fire statistics begin to fall.

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