I recently got a copy of a letter put out by Siemens claiming they have perfected AFCI breakers that can detect both series and parallel arcs.
So, if manufacturers claims are to be believed, AFCIs now:
Detect arcing faults in series with a conductor.
Detect arcing faults between hot and neutral conductors.
Provide some protection against high-resistance connections by detecting when the fault progresses to an arcing or ground-fault.
Provide some protection against sloppy wiring (multi-grounded neutrals, high-resistance grounded hots) with the GFP function.
Assuming this is all true, what is the feeling on pushing to have these things adopted wholesale for the 2008 NEC? On the face of it, it seems like there is at least the potential to provide much safer installations. Maybe it would be worth the added cost.
John, What reason is there is start believing the manufacturer's information at this point in time? They have been distorting the facts on this issue for some 13 years now. Also has anyone seen this new combination breaker from Siemens? As far as improving safety, they would have a small impact if the actually work, however 85% of the dwelling unit fires of electrical origin occur in dwelling units over 20 years old. The AFCI is not a fail safe device and I do not expect that the fancy electronics in the device will still be functional in 20 years or more when it may be called on to prevent a fire. Yes I know that the instructions tell the homeowner to test the device using the test button once a month. I expect it will be a rare case where that actually happens. Don
There is not one bit of statistical evidence (from the existing installed AFCI's) that expanding the use of AFCI's will make a big differance. I believe the panel vote had 4 negatives against the proposal, but that wasn't enough to defeat it.
I agree with Don 100%, especially about the testing & longevity issue. A couple of years ago, a survey found that about 17% of the installed GFI's don't work which tells me that no one is pushing the test button or they are ignoring the results.
Few things are harder to put up with than the annoyance of a good example.
Has anyone out there had a service call where an AFCI was tripping and the problem was determined to be an arcing fault on the circuit? Just curious if the calls have started coming in now that more of the breakers are getting installed.