Nate Nagel wrote:
On 07/03/2013 06:07 AM, Robert Green wrote:
wrote in message

stuff snipped

The science of AFCIs is proprietary and they are not all the same but
they look at current, detecting short duration spikes

I'm confused now. Do the AFCI's use RF at all to detect arcing conditions?
I've been trying to find some descriptions or patents that detail how they
work without much success. One interesting site I found:

http://electronicdesign.com/electrom...rk-controversy

said that one user, who thought his AFCI was "nuisance tripping" discovered
that it was actually tripping because of a dangerous condition in his
bathroom.

"I read all the available information on the Web running into all manner
of grousing, but I also saw an article explaining what the breaker is and
what it does. Encouraged, I started looking for the culprit. On and off it
took me two weeks to separate the circuits to discover that an improperly
installed GFCI socket in the bathroom (on the bedroom socket circuit)
compressed the hot wire against the grounded socket box," he said.
"Old Romex insulation fractured, crumbled, and allowed arcing to the box. I
do not know how long this condition lasted, but now it is fixed," he added.
"In six months, neither of the two breakers disconnected. I am a convert and
I would encourage retrofitting AFCI breakers, especially in older
installations."

Maybe it IS time to switch to AFCIs!

--

Bobby G.



In my limited experience with them, I haven't had any issues. Every time
it's tripped it's been because of a legitimate problem.

Also, the amount of improper wiring that I found in my last house,
combined with simple age and the tendency for old 60C wiring to become
brittle in ceiling light boxes, makes me think that in general they're a
good idea. I lived in my last place for almost a year before going up in
the attic and doing a serious investigation of the wiring, what if
something had happened before I started fixing everything? And since
everything was working, a homeowner less inclined to do it themselves
could have lived there a decade or more unaware of any potential issues
(as I believe to be the case of the previous owners.)

No, they're not a replacement for proper wiring products and methods, but
in a structure where the wiring is apparently in good shape but known to
be old and not up to today's code, it makes sense. For newer houses
where everything's right, it might be overkill, but won't hurt anything either.

nate

I installed arc fault breakers on two legs, which included both bedrooms.
This was old wiring. One leg would trip on occasion. I called that leg the
big mess, because if you saw it, that's what yo would call it. Most if that
has been replaced, so far so good.

An arc fault breaker is not also a ground fault is it. Are there some ?

Greg