Don't hold back! Tell it like you see it! :thumbsup:
I think this site should create an AFCI forum all to itself...
Trust me what I am about to disclose it the tip of the iceberg, I could go on for days at a time. Anyway, the general details:
1. It has never been proven arcs are responsible for dwelling fires. Never. Most fire investigations are not completed by a qualified expert to begin with. When the CPSC asked NRTLs to look into dwelling fires the CPSC funded them to research arcing, not the whole scope of potential fires.
2. The majority of electrical fires are believed to be caused by glowing connections. Glowing connections produce no arc signature and do not just open circuit on their own like others have mentioned before.
3. Arcing staples have also never been proven. While arcing staples or nails sounds like a plausible theory having received much investigation, pyrophoric carbonization from an energized staple or nail has never been investigated with public disclosure. A staple energized with 120 volts trickling current into wood produces no arc signature, yet it can easily turn wood into charcoal over time resulting in fire. When investigator find a smoldering stud, its easy to assume an arc fault having been conditioned with propaganda. Of further not, when UL did testing on over driven staples they discovered that in order for arcing to take place at 120 volts the path must be carbonized with a 1kv plus voltage spike for a long enough duration. Such a spike will destroy the electronics in an AFCI, so even if it were true in the real world the AFCI is fried incapable of stopping it.
4. The rest of the world has a low cost solution: A none electronic sub-main RCD with megger testing required for all new circuits or those having been repaired. Such testing catches over driven staples and wiring errors, while the RCD catches any arc faults to ground.
5. When UL did testing, they determined that all over driven staple faults in testing involved the EGC and thus a condition capable of tripping an RCD. RCD (30/50ma GFP) does all the work and does not nuisance trip.
6. Some manufacturers have taken GFP out of AFCIs which leaves not only unproven arc logic, but also the inability to catch wiring errors like crossed circuits and ground faults no involving an arc.
7. Arc logic is in its infancy. Not only that, the logic used in residential AFCIs is way to primitive. This results in nuisance tripping on NRTL listed appliances.
8. AFCIs drive up cost and back fire;
a. Home owners hire unskilled handyman because their none AFCI quotes are cheaper than an electrician who is forced to follow code.
b. Nuisance tripping AFCIs get taken out, sometimes even by electricians.
c. Electricians have to spend more money on wire and labor because double pole AFCIs are to expensive or don't exist.
d. Electricians and contractors are now wiring to the minimum 3va per foot, meaning fewer circuits taking on more burden. While its true some contractors have always wired to the minimum, that number is going way up.
e. The obvious: Each $37 AFCI breaker adds cost to a new home or panel upgrade.
9. A fraction of the money being used for the above can go toward a low cost sub main GFP (which does all the work) and/or with a requirement for electricians to test all new circuits for good insulation (a quick procedure only involving a one time megger purchase).
10. The rest of the world does option #9 costing less and having lower fire statistics while foreign electricians laugh their heads of at the NEC.
11. The CMP was presented with false, tailored evidence being mislead.
I will write more but that's the rough overview.