Hey Scott,
This is all somewhat "newer" NM. Plastic sheathing like you see nowadays, but probably 25 years old.
The marking were on every wire, every wall, even the ceiling! So, though your idea of maybe a south facing wall getting hot seems to make sense, unfortunately not in this case due to it being everywhere. All the wiring seems to be fine. Put an arc fault breaker on each of the circuits just to see if there where any problems, but the breaker holds.
So, I am guessing this one probably has something to do with the extreme heat the lighting strike caused. Would have thought a strike like this would burn the wire like a firecracker fuse, but I guess the lighting is over so fast that the split second of heat just overheated the wires. No big loads on any of the circuits, so not thinking this is a case of bad breakers letting the wire get way overheated all the time.
Thanks for your input!
Jim
