I did an inspection yesterday and the copper wire in the outside panels ws dark black. At first glance I though the ground wires were insulated. On closer examination, there had all turned black. This was seen in both the service panel and the pool electrical panel. The copper in the inside panel was normal as was the copper on the air conditioner coils.
The home was built in 1997 so before most reports of Chinese drywall and if that were involved, I would have expected the copper inside the home to be affected.
Does anyone have an idea what might cause this and if there is a problem that I should report?
The first photo is the outside panel and the second is the inside panel.