Many years ago, I went on a service call where the customer was complaining of bright/dim lights in their home.
This, as we all know, usually means a bad neutral.
When I took the cover off of the panel I noticed an arcing between the GEC and the panel where it passed through this 1/4" (or 5/16") hole.
It must have been arcing for some time because the GEC (solid copper #6) was discolored due to heat as was the metal of the panel wall.
I did find out that the neutral was bad and ended up upgrading the SE.
Ever since then I've been using a 1/2" NMC cable connector. I believe that that arcing wire could have caused a fire if it had been near something combustible and that it would be better if the GEC was secured as it passed through the wall of the panel.
