Hi there. Back again with a new problem.

My wife was doing the laundry and I was working near the circuit breaker
panel. When she turned the machine on I heard a loud buzz from inside the
box. Less than a second long. I had her turn the machine off, took off
the panel cover and watched as she turned the machine back on. I saw arcing
at the left-handed side of the panel at the point where the heavy black
cable from the street enters the box. I had her turn the machine on and
off and it happened again. Then I pushed the black wire right where it
enters the clamp and it hasn't happened again, despite having all the same
lights and appliances on.

I am thinking the clamp has loosened over time. I am going to get a
well-insulated screwdriver, put on very heavy rubber gloves and am going to
try to tighten the clamp which may have not been tightened in 40 years.

Does the power *really* need to be killed at the meterhead? I've changed
out breakers without killing main power (so much frikkin' stuff needs to be
reset after a power shutdown that I hate doing it)?

Anything else I should consider? Is the washine machine motor about to fail
and is drawing a huge amount of current at startup? How do you even measure
the inrush(?) current in such a case. Would pressing on the wire near the
clamp cure it temporarily or is some other process in play?

What would account for it happening twice and then not happening again. The
only real intervening act was to push on the wire jacket at the point it
enters the clamp on the circuit panel. Very strange.

TKS