Afci's

[vsparks]

Regarding protection offered by AFCI's I was confused by a statements found on your website and in your book, "Understanding The National Electrical Code" -2002.

Website Q/A: What type of arcs are the most common factors in electrical fires, and will today?s AFCI circuit breakers detect these faults?

An AFCI is designed to detect and clear a line-to-neutral fault under conditions where a standard circuit breaker might not (3 to 8 cycles as compared to 600 half-cycles, depending on the available fault at the failure). Loose electrical terminations and connections should generate enough heat to create a line-to-neutral fault or a line-to-ground fault, which will be detected by the AFCI or GFI circuitry.

2002 Textbook, P.61: "WARNING: AFCI protection devices are not designed to prevent fires caused by series arcing at loose connections to a receptacle, switch, device or in a splice".

Are these two statements contradictory?

Thanks,

vsparks

 

[Dennis Alwon]

There are two kinds of arc faults that are now, in the 2008 NEC, required to protect circuits in most of a dwelling unit. These are series and parallel arc faults and I would guess that the series arc fault would be the more common.

Here is an article by Mike Holt that may explain things better for you.

 

[cowboyjwc]

Also an AFCI still may not prevent a fire. Once it has arced, and it has been detected, the breaker should trip, but the conditions for a fire may have already been set.

 

[al hildenbrand]

". . . on your website and in your book . . ."

Welcome to the Forum.

Your inquiry implies that you are addressing Mike H. You are rather unlikely to get a response from him through the Forum.

However, as Dennis & John have already demonstrated, there is a great resource of knowledge and experience in the members of this Forum.

Your observation about the AFCI behavior claims, and the caveat about series arcs, was a source of some frustration with the Grand Concept of the AFCI as sold to us by the manufacturers and special interest groups.

 

[mivey]

There are two kinds of arc faults that are now, in the 2008 NEC, required to protect circuits in most of a dwelling unit. These are series and parallel arc faults and I would guess that the series arc fault would be the more common.

Here is an article by Mike Holt that may explain things better for you.

Mike also recommends: Earl Robert's Overcurrents and Undercurrents, All about GFCI's, AFCI's and Similar Devices

Dennis,
Re: "4 Out Of 3 People Have Trouble With Fractions"
The other 50% have trouble with percentages.