Ran into this today. It appears the connection on one side of the entrance cable is melted, as it is inside the main panel. What might cause this and how serious is it?? Thanks
Looks like a bad crimp by the AHJ. Power company…
You’re no sparky Todd 
My thought was a poor connection as well, but I ain’t no sparkie neither. . .
Hey Pope , stop beating me up. I have made a connection or 2 in my time LOL
I agree with the “non-sparkee”
This type of connection is not always performed by the POCO. Sometimes the conductor is not always inserted far enough inside the crimp connector. This may be the case here. The picture of the inside location is hard to see, so I am not too sure what may have caused that situation.
Is the third picture the main ?
I found a crimp the other day that looked exactly like that one.
Also, I have had to replace more than one panel in my day for exactly the same reason as pic #3. Once the buss starts to pit and/or overheat there is no turning back.
Lightening Strike?
That was my first though but I have never seen lightening being selective it would take out every thing including the mast.
I think it was a previously reported loose ar incorrect joint .
Roy Cooke
I guess it is entirly possible it was a lightning strike…but I would also not rule out a overloaded breaker that overheated and melted the back plastic holder. on the connection at the drop…as others have stated it could simply be a poor connection which is a compression crimp done by the POCO…not the electrician in most all cases…can’t say all as who knows is some little counties somewhere out their…lol
My experience is on a lightning strike it does not single out a simple breaker contact point like this image from what i can tell…it usually melts down a larger area if a direct hit…did the home not have a proper GEC and System on it?
Anything entirly possible…one this is for sure…regardless it is must be replaced at this point and reported as such.
Thanks all! I had suggested further evaluation and replace/upgrades recommended.
Current 100 amp., 24 breakers with 4+ doulble taps, + feeding one 60 amp. sub.