On 2/22/2016 11:44 AM, Ralph Mowery wrote:
"Texas Kingsnake" wrote in message
...
Gentlemen and women:

I am not sure if you all remember, but I had the circuit breaker panel
with
the bad aluminum feeder cable that was shooting sparks.

We finally put the new panel in yesterday -- by *we* I mean *I* stood
around
while my electrician buddy did the work. We used 6 AFCI's in the panel
for
the bedroom and kitchen circuits. When it came time to power the panel
back
up, AFCI breaker number 6 refused to latch.

Here is the big question: How do you locate the arc fault that's tripping
the breaker? In this old house the wire is buried deep in plaster walls
and
routed from the basement up to the attic and back down again, FWIW, it's
not
K&T, just old cloth-covered wiring from the 40's. My buddy had a word for
it I had never heard before -- ragwire.

TKS


First thing is to swap wires at the breakers to make sure the new one is not
faulty.

Then find all the outlets that the breaker goes to. Take them loose one at
a time. Not really the outlets, but the wires going from that outlet to the
next outlet. This will isolate how far the 'good' wireing is.

+1

Make sure you know EVERY place the branch circuit goes!

If you think you can visualize how the wires have been run
(i.e., from panel to this box, then that box, then the next box, etc.)
then you can theoretically reduce the number of "guesses"
by "cutting the unknown portion in half" with each guess.

E.g., if you think the circuit runs:

Box A B C D E F G H I ...

then make your first cut at E (or thereabouts).
This will tell you if the problem lies in the
Box-A-B-C-D portion of the branch circuit or the
E-F-G-H-I portion.

[Note that there may be more than one problem!]

If the problem persists in the Box-A-B-C-D portion,
then cut this at B. Now you can narrow it down to
Box-A-B or C-D.

As you will probably be using the (proven non-defective!)
AFCI as a "tester", if the portion of the branch circuit that
you've isolated appears to have the problem (i.e., problem
goes away when you cut the circuit at E -- suggesting problem
lies in E-F-G-H-I), then you will have to reconnect that
portion (verify that the problem REAPPEARS as your tinkering
with it could have "fixed" the problem!) and now find
a spot in the "suspect" E-F-G-H-I segment to cut -- like
at G.

This then isolates the problem to H-I or Box-A-B-C-D-E-F-G
(but you already know Box-A-B-C-D-E is good so it's really
just E-F-G!)

The alternative approach is to isolate 'I'. If now tests
OK, then I was the problem. Otherwise, isolate H, then
G, then F, etc.