No resistance at 500v
Just because the panel, the pipe and the wire have been there thirty years for the insulation to be compromised, but there you are!
Trips set at minimum but the main trips first anyway
Looks kind of wet.
XHHW-2 is a much better insulation than THHW for wet locations. I have seen several failures of THHW in underground conduits, which around here, are water filled. Plus XHHW-2 is 90 C rated for wet locations and THHN in a wet location is not.
