daokfella wrote:
Thanks Doug,

This is copper wiring. I do notice on the buss bar that there are two
sizes of screw terminals. The ones containing two wires are of the
larger size. However, the point is taken. When I do my "housekeeping"
on the panel, I will try to keep it one wire per terminal. It does
look like, however, that there may not be enough terminals for each
circuit to be in it's own, but I'll get a closer look. The last time I
worked closely with the panel is when I installed a 50A breaker and
wired in a sub-panel for my finished basement.

It definitely seems like a poor connection on the buss since it worked
fine for a week after tightening it. However, this morning it was back
to flickering and arching.

That may be indication of other connections on the circuit having
similar problems, too (although I guess you're seeing arcing at that
same neutral in the box so that would definitely be a problem).

See my other response on cleaning terminals and wires to remove
corrosion/oxidation. If the wires have been flattened by previous
connection might snip off to a new end if have a little slack. Moving
one or more to alternate location on the neutral bar is a possibility
although shouldn't be necessary unless the arcing has significantly
damaged that connection location. It is likely that if there has been
sufficient arcing you have seen it that it has caused some oxidation of
the surfaces. If so, may not be making good contact even if you did
retighten connections.

Whatever, don't give up until resolve it as (I'm sure you're well aware)
this ain't good...

--