RBM wrote:

A customer called with an intermittent electrical problem: The electric
range and refrigerator on occasion stop working, then start working for no
apparent reason.
It's obvious that one of the hot legs is opening, as that would be the only
common denominator between a 120 volt refrigerator circuit, and a 240 volt
range circuit. The customer was also unaware of a multitude of other
circuits that were also dead. Usually when I get these calls, I start with
the connections in the most hostile environment, 1) The overhead service
connections, 2) The outdoor meter socket, then check the main circuit
breaker. In this case the culprit was the main circuit breaker, which by all
outward appearance, looks fine. There was antiox paste on the conductor
connections, no hissing or crackling sounds, and the breaker was cool to the
touch. Upon removing the breaker, the problem became clear. A bad connection
(factory) between one pole of the breaker and the panel buss, over time
caused overheating and annealing of both the panel buss and the copper
contact of the breaker. Pictures to follow:
http://i17.photobucket.com/albums/b9...ldamage006.jpg

http://i17.photobucket.com/albums/b9...ldamage008.jpg

http://i17.photobucket.com/albums/b9...ldamage003.jpg

http://i17.photobucket.com/albums/b9...ldamage005.jpg

Eeew! This is why I stick with Square D QO equipment. Even then I do
inspect items as I'm assembling and installing them.