Afci...questions you have never answered

[Ian Gills]

I changed the circuit breakers on my Square D QO panel for the heck of it (they were all getting old).

But now having worked with the panel safely, I was thinking about changing some of these breakers to AFCIs.

Assuming my QO AFCIs will fit in my QO panel, I have a few questions.

I know where they should be used (on all outlets in the bedroom) and at least two circumstances where they should not (with a shared neutral, or on cicruits larger than 20 Amps - I do not think they make them that big).

Are there any other cicruits where an AFCI should not be used? In the kitchen? For a sump pump? The furnace? On GFCI-protected receptacles? Lights? Or can they be used anywhere?

And do AFCIs incorporate some degree of GFCI protection? I know in theory, no, but on the instructions the AFCI stated that it did not meet GFCI protection in accordance with Section A (or something like that). Does that mean it provides some GFCI protection, but it is just not that good?

It will be interesting to see how my AFCIs hold up to my old AC wiring. My venture may be a complete waste of time. I am guessing only small imperfections are needed to generate a trip.

In Europe, scratched insulation can be enough to trip similar breakers there and their use is often impractical in older houses, even where the wiring is perfectly safe.

My next project will be to rewire the stove (without an AFCI, don't worry). It took me ages to find 6-gauge wire with 3 conductors and a ground. And it cost a lot. Lowes did not stock it. But I have found some and will be moving over to a four-wire system. I am doing this to stay code-compliant, but why are four wires safer than three? Is it because of the small chance that the range develops a fault and the earth/neutral becomes disconnected from the panel?

The stove in my neighbor's house appears to be wired with lamp wire. But that is another story.

[Greg Fretwell]

Yes AFCIs do have ground fault protection at the 30ma level (class A is 5ma)
Usually nuisanse trips that didn't trip the regular breaker can be traced to a neutral/ground fault. Suspect those ceiling boxes with that big wirenut all the neutrals connect to. That is one of the few times I suggest taping up a wirenut. If one of those wires touches the hickey or a ground wire that will trip the AFCI.
I am not a huge fan of the AFCI they sell right now. Like anything else electronic you never want to be on the "bleeding edge" of innovation. The current AFCI is expensive, still under developlent/testing and unproven.
When they shake all the bugs out and establish some uniform industry standards I will buy in. ... but that may just be me. I bought a Betamax or four too.

The 4 wire to the range/dryer is a good idea. Yes you are worried about an open fault in the neutral energizing the case of your dryer.

[Ian Gills]

Thank you very much. Very informative.

[Greg Fretwell]

BTW if your goal is to incorporate the 2008 code in your plan you should AFCI all circuits and additionally GFCI all circuits in the unfinished areas, including freezers, sump pumps and washing machines.
Good luck!

[Ian Gills]

Will do, even my AC condensate pump in the basement is GFCI protected.

And all this from someone that does not even have mains wired smoke detectors. Irrational eh?

[Greg Fretwell]

I run everything in my garage on GFCI too and I have a fridge out in the pool bar on GFCI so it does work.

[Paul W. Abernathy]

And be aware you can get AFCI's ( FireGuard ) that do have AFCI and Class A GFCI as well.....they are available.

[Michael Larson]

Originally Posted by pabernathy

And be aware you can get AFCI's ( FireGuard ) that do have AFCI and Class A GFCI as well.....they are available.

Link please?

[Paul W. Abernathy]

Hey Greg....I found out today JUST how much I am still learning the NEC even after so many years...I was put in a position where I was grilled by a few folks today with the technical answers in front of them......about 50KV systems and up, showed me a few poorly done drawings and expected me to say pass or fail with no NEC present...random elaborate transformer questions...about protection, sizing and so on...again no NEC present.. and high rise building installations....BOY i realized even seasoned code guys have to study........yep they expected me to know it all by memory....no NEC book was made available to me.....I am a consultant meaning I can find the answers in the code and inter. for clients....not commit the entire BOOK to memory...man I left felling about 2 inches tall....and I only missed a few...but boy it made me feel small today....

Gotta love the CODE...

[Paul W. Abernathy]

Originally Posted by mlarson

Link please?

lol....well I know about them because I STUMP them for Eaton.....about 7 times a month...lol...just did on Monday in Detroit and Thursday in Jacksonville Florida....

Do a google on " Fire Guard by Eaton "...I will see if I have it for ya....again it's eaton specfic...probably should have said that first huh....lol..sorry

[Michael Larson]

Originally Posted by pabernathy

lol....well I know about them because I STUMP them for Eaton.....about 7 times a month...lol...just did on Monday in Detroit and Thursday in Jacksonville Florida....

Do a google on " Fire Guard by Eaton "...I will see if I have it for ya....again it's eaton specfic...probably should have said that first huh....lol..sorry

That's the problem Paul, when I have looked for the mystical beast, I can't seem to find one.

[Paul W. Abernathy]

tends to be an issue with suppliers more so than Eaton really.....we have them at our local Rexel Office...Here ya go....http://www.fireguard.info/

The FIRE-GUARD™ Arc Fault Circuit Interrupter (AFCI) is a residential circuit breaker with an integrated processor which recognizes the unique current and/or voltage signatures associated with arcing faults, and acts to interrupt the circuit to reduce the likelihood of an electrical fire. With the Cutler-Hammer FIRE-GUARD AFCI, protection from arcing faults is combined with conventional thermal and magnetic overloads as found in standard residential circuit breakers protecting wiring from excessive heat or damage due to overloading or short circuits. FIRE-GUARD AFCI can also be equipped with 5 mA ground fault protection to protect from personal shock hazards. Now, there is a residential circuit breaker that provides protection from arcing faults, conductor damage due to thermal overloads and short circuits, as well as 5 mA ground fault protection in one integrated design.

[Michael Larson]

Thank you

[Paul W. Abernathy]

most certainly welcome my brother......

[Greg Fretwell]

I did road shows and some standup for IBM. There is nothing like teaching something to learn it. Good students should always be challenging the teacher. It is the only way you stay sharp. There is nothing wrong with getting caught as long as you can get the real answer out there in the end.