On Fri, 03 Feb 2006 21:17:42 -0000, (Chris
Lewis) wrote:

According to Ajax :

Chris, I think that you were very close to what we discovered was the
problem. After replacing the 60 amp double pole breaker with another
new breaker, it continued to trip.

Glad you found it. The issue here was that conditions were such that slight
moisture/movement variation provided intermittent conductivity (or arc)
between the nicked conductors, and at other times, there wasn't enough
carbon path to show up on the instruments.

It was intermittent to the degree that it passed a test by an
Ideal(TM) circuit analyzer. If any of the conductors were shorted or
open at the time the Ideal tester would have found it.

This meter also measures ground to hot current and it was showing a
very low reading, something like .12 volts. Anything under 2 volts is
considered to be within the normal range. After the cable was repaired
the ground to hot voltage went to zero.

Aparently there was some leakage between ground and hot all of the
time, but it was not enough to cause the breaker to trip most of the
time.

Lesson: Never trust a plumber with anything sharper than a can of PVC
glue.

Heh. The last time I did a full house rewire (actually a major duplex
rewire, two systems), every time I came over for a wiring stint, the plumber
had managed to do something awful to the wiring I installed the previous
time. Like the time his 3" drill caught a wire, and pulled a _whole_
circuit, boxes and all, out of the wall.

At one point, about 50% of each day was spent fixing what the plumber
wrecked from the last time.

[He really was a damn good plumber. It was a huge and difficult job. He
apologized, I eventually forgave him ;-)]

I have always though that the electrician should be the last trade on
the job. Plumbers can do a lot of damage that often is not obvious
until someone finds a dead circuit or worse.