Just to clarify for everyone involved: Sarcasm often doesn't come through clearly in text discussions that span different regions of the country or the world. You don't hear tone of voice, you don't see nuances of body language. You can't see the raised eyebrows and the half smile.
I am pretty certain that
@macmikeman was being sarcastic with:
and we all know they work so terribly well in just such a situation where the is a tiny nick in the insulation, that we are all thrilled to cough up the extra 50 bucks . I know this because electrical inspectors told me so.
I am pretty certain that
@ptonsparky was pointing this out.
I am pretty certain that
@jap is not being sarcastic at all, and is expressing that AFCIs won't help with nicked insulation, which I think means that AFCIs won't do their claimed job.
But since reading sarcasm requires reading between the lines, I'm not absolutely certain of the above.
It seems to me that if you have nicked insulation, in a stable system where the exposed conductor never touches anything else, that you don't have a fault and have nothing to detect. The _risk_ from nicked insulation is a small high resistance arcing fault occurring which causes heating and fire. The (faint) hope is that AFCIs will do a better job of detecting these sort of low level heat producing faults, and protect the wiring from faults caused by things like nicks, loose connections, etc.
Most people on this board (myself included) are less than sanguine about the true ability of AFCI devices to make a sufficient difference to be worth their cost.
-Jon