View Full Version : ARC Faults

Thom Walker
05-07-2007, 05:34 PM
I smelled something burning during an inspsection today. It was kind of a combination of rubber and compost. Then I realized I was accidentally thinking again.

Regarding AL wiring and the outrageous cost to electricians for the cost of the Copalum Crimp equipment. (I'm assuming the electricians are telling me the truth.) And I was thinking about how many homes still need to be updated. It was thinking of two things at once that started the fire, I suppose.

Anyway, for you electricians and others: Is there the possibility that ARC fault breakers could be a reasonable answer to the aluminum arc risk? Obviously, they would have to be available in more than 15 and 20A sizes. This guy hints at it, but doesn't commit.
Have We Sparked Our Last Home Fire (http://www.expertlaw.com/library/fires/home_fires.html)

Jerry Peck
05-07-2007, 06:38 PM
With the newer ones needed to meet the 2008 NEC, the answer would be 'those fires would be (if arc fault circuit protection was installed) reduced dramatically'.

I would not say 'eliminated', but 'reduced dramatically' would be a definite plus.

Of course, there is the problem of installing AFCIs in old panels, which can be corrected by the exception (which is why the exception is there) to requiring "the entire branch circuit" to be AFCI protected. That exception allows a short run, in metal conduit, to a box where the AFCI protection would be installed, the conductors in that short run are also 'part of that branch circuit', thus those need to be excepted out of 'the entire' branch circuit.

Thom Walker
05-08-2007, 06:05 AM
Thanks for responding.

While trying to find out more about the potential use of AFCI with Aluminum wire I found the article at the attached link. Not only is it a good argument for expanded use of AFCI. It also has several clear and concise definitions of electrical problems.


05-08-2007, 06:55 AM

good article


Jerry Peck
05-08-2007, 04:36 PM
I had 4 AFCIs stacked yesterday. They were "buzzing". I don't believe that is "normal" so I punted to electrician to look at it. Also, is it 3 that is the max # of stacked AFCIs?

There is nothing (so far that I am aware of) "in writing" which says stacking them is not allowed.

HOWEVER, all manufacturers I've talked to have acknowledged that 'it's a "good idea" not to stack them on top of each other, that at least one or two regular (non-AFCI) breakers be installed between the AFCI breakers' to allow for heat dissipation.

The newer AFCI breakers are supposed to be operating with a lower energy use (lower heat output) circuit in them, which should eliminate this problem, which is good, considering that it will not be much longer before all 120 volt circuits will require AFCI breakers.