Question from UL about AFCI breakers.

[Bryan Holland]

Good Morning Everyone,

Please see the question below posed by Mr. Fecteau of UL.

I have not had any personal experience nor have received any reports of an AFCI breaker actually functioning properly due to a real arcing / faulting condition. I can say that I have first hand knowledge of AFCI tripping due to unintentional ground faults located somewhere on the protected circuit. The far majority of the cases resulted from the equipment grounding conductor coming in contact with the grounded (neutral) terminal of a receptacle. I can say without a doubt that particular aspect of the device works. These were conditions that may have gone unnoticed on a regular overcurrent device.

Since the adoption of the 2002 NEC here in Florida, I would rate the number of troubleshooting issues / complaints about AFCI’s in this order:

1. Defective device

2. Nuisance appliance tripping (vacuum cleaners / UPS’s / refrigeration equipment)

3. Unintentional Ground-faults.

If you have any positive accounts or reports, please feel free to respond directly to Mr. Fecteau.

Thank you,

Bryan Holland

________________________________________

From: Jeffrey.Fecteau@us.ul.com [mailto:Jeffrey.Fecteau@us.ul.com]

Sent: Tuesday, July 12, 2011 5:22 PM

Subject: AFCI ?

I am looking for any first hand experience where an AFCI worked. We have all heard stories of nuisance tripping, but what I am looking for is information on where the AFCI performed properly. For example, an actual arc fault or damaged conductors that had a potential to start a fire.

If you have any stories or information, I would like your permission to possibly quote you in an article.

Thanks

Jeffrey A. Fecteau C.B.O., E.C.O

Lead Regulatory Engineer

Regulatory Services

Underwriters Laboratories

 

[ICE]

A few years ago, I had a case where a dwelling had been gutted and rewired without permits. The work looked great. The only concern that I had was protection of the NMC. The electrician wasn't a slouch and assured me that he installed dottie plates where needed. I gave them the option of removing drywall to see all of the NMC or install arc fault circuit breakers on every circuit. They chose arc faults and sure enough there was a nail that hit a cable in a garage wall and the arc fault tripped.

 

[Francis Vineyard]

I have not read it thoroughly but this report answers the statement “I have not had any personal experience nor have received any reports of an AFCI breaker actually functioning properly due to a real arcing / faulting condition.”

CONCLUSIONS

The primary goal of this paper was to describe what a Combination AFCI circuit breaker can do, while also clarifying what it can’t do. The features of the Combination AFCI, and the earlier Branch/feeder AFCI, are listed in Table 1. Neither provides series arc protection, the Branch/feeder provides the extra important feature of 30mA ground fault protection.

The paper goes on to explain, but not justify, how the Combination AFCI came to be mandated, while the Branch/feeder that provides more protection at less cost is disallowed. The key drivers behind this were the AFCI manufacturers, their NEMA organization, and UL. The author hopes this paper will stir discussions amongst the principals and correct any errors that were made concerning their products’ performance. This would also include supporting removing the Combination AFCI mandate from the NATIONAL ELECTRICAL CODE (NFPA 70).

Finally, the author, having participating actively during the AFCI development, would encourage the IEEE engineering communities of these great institutions to become more engaged to insure their codes and standards representatives fully understand the technical issues. These are their products; they have a responsibility to insure their products are not inadvertently misrepresented.

Source: http://www.combinationafci.com/resources/doc_ieee_combination_afci.pdf



Francis

 

[Dennis]

I would like to add that not all afci breakers have gfci protection at 30 ma. Ge has taken the gfci out of their afci. I believe they did this so that you are able to use 2 single pole afci breakers on an mwbc. This saves them from having to make dp afci breakers.

 

[rogerpa]

I would like to add that not all afci breakers have gfci protection at 30 ma. Ge has taken the gfci out of their afci. I believe they did this so that you are able to use 2 single pole afci breakers on an mwbc. This saves them from having to make dp afci breakers.

Which AFCI's (Model #'s) contain GFCI protection? Thanks.

 

[Dennis]

As far as I know they all do except GE. But remember this GFCI does not satisfy the NEC requirement for protection of personnel (art 210.8). If GFCI is required on the circuit then you still need to add that to the circuit.