AFCI and/or GFCI protection

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flick

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I've read numerous times that AFCI's include GFCI protection at the same time. However, is the level of GFCI protection the same? I'm a bit concerned about this.

From the Siemens website :
Differential sensor thresholds vary by manufacturer but are typically 30mA or less. Siemens has recently changed the design of the differential sensor used in our AFCIs. AFCIs produced before July 2002 have a threshold between 7mA and 12mA, and AFCI produced after July 2002 have a differential threshold closer to 30mA.

The reason I am concerned is for old work. I run across the old BX (not suitable for grounding) in some homes that the customers cannot afford to rewire. I like the idea of recommending AFCI breakers to protect these old installations but if the GFCI protection level is approximately 30mA, that seems too high to me for personnel protection. Doesn't a class A GFCI trip at approximately 5mA?

What are your thoughts and recommendations on this matter?

Thanks for your replies and advice.

flick
 
Re: AFCI and/or GFCI protection

Your correct the present AFCIs have GFCIs in them but they can not be used for personnel protection.

You can use an AFCI breaker to feed a GFCI receptacle and provide GFCI personnel protection that way.
 
Re: AFCI and/or GFCI protection

Ok.....at least I got something right! However, does the AFCI protection work "through" a GFCI receptacle if that receptacle is feeding other receptacles downstream? I am guessing that it would, since the AFCI is looking for a arc "signature" and the GFCI receptacle is basically a closed switch as far as passing current downstream. If this is the case, then the combination would work quite well. However, will feeding downstream receptacles without an equipment ground interfere with the AFCI's ability to open on a fault?

Thanks again for the help.

By the way, I've read with interest some of the discussions of GFCI protection of grounding type receptacles that do not have an equipment grounding conductor. I personally am of the opinion that this is OK since the level of personnel protection is much higher than a two-wire circuit with no equipment ground. I realize that this is acceptable according to the NEC, but I was interested to note that some people do not believe this should be done.

flick
 
Re: AFCI and/or GFCI protection

Originally posted by flick:
However, does the AFCI protection work "through" a GFCI receptacle if that receptacle is feeding other receptacles downstream?
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Yes, for the reason you stated, to the AFCI the GFCI is just a down stream closed switch.

Originally posted by flick:
However, will feeding downstream receptacles without an equipment ground interfere with the AFCI's ability to open on a fault?
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The lack of an EGC will not effect AFCI operation.

Thanks again for the help.

Originally posted by flick:
I've read with interest some of the discussions of GFCI protection of grounding type receptacles that do not have an equipment grounding conductor. ......I realize that this is acceptable according to the NEC, but I was interested to note that some people do not believe this should be done.
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Fick I did not see anyone saying you should not place GFCI protection on replacement receptacles.

What some of us pointed out is that even if you do that it is still an NEC violation to plug in equipment that is required to be grounded into that replacement receptacle.

That is unless you know of a section that relieves the requirements of 250.114. :)
 
Re: AFCI and/or GFCI protection

Thanks for the responses iwire. All that being said, what would you do? Would you replace the receptacles with grounding type and mark them as required "gfci protected" and "no equipment ground" or would you stay with two contact receptacles? The home owner will not pay attention to the rules of 250.114, even if these rules were explained. On the other hand, if the devices are non-grounding receptacles, the homeowner would probably just put a cheater in and plug whatever cord into it anyway.

flick
 
Re: AFCI and/or GFCI protection

Can a GFCI breaker protect grounding type rec. on those branch circuits that don't require AFCI protection?

Or, is the cost of 6mA dual-function breakers (not Seimens) that much greater than single use AFCI breakers?
 
Re: AFCI and/or GFCI protection

Roger have any true combination AFCI / GFCI (5 ma) devices actully made it to market yet?
 
Re: AFCI and/or GFCI protection

Yes, I have a listed AFCI/GFCI cutler hammer circuit breaker, I have had it for 3 years, it was $38 at the time, an AFCI CB was $35.
 
Re: AFCI and/or GFCI protection

I found this on the Cutler-Hammer website. I sure wish Siemens had this option. Would come in quite handy!


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.
 
Re: AFCI and/or GFCI protection

I've read numerous times that AFCI's include GFCI protection at the same time. However, is the level of GFCI protection the same?
Click to expand...
The standard AFCIs have GFP and not GFCI protection built in. The term GFCI should be reserved for "people protective eqquipment". A GFCI has a ground fault trip level of 4 to 6 mA, but the GFP in an AFCI has a trip level of 30 to 50 mA.
Don
 
Re: AFCI and/or GFCI protection

One might think, that it would not be long before all breakers would be AFCI including the main.
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I hope not...they are not yet a proven item. The combination type that is required for installations after 1/1/08 are not yet on the market. And would you really want a 30mA ground fault anywhere in the building to trip your main?
Don
 
Re: AFCI and/or GFCI protection

I installed a couple of new Siemans afci breakers yesterday. I was suprised to find that they did not trip upon using my solonoid tester between hot and ground. Now I know why since they have recently upped the threshold, I guess that is now above what the Knopp tester draws. Thanks for this info. I was thinking of returning those afci breakers to the wholesale house, on just the possibility that they might have been defective even though the test button worked. Now I am not worried about that.
 
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