Found a family of squirrels living inside a main panel last month
I was doing a service upgrade in an old house in Tacoma and when I opened the outdoor panel, three baby squirrels just stared at me from a nest of chewed up Romex. The homeowner had been hearing scratching for weeks but thought it was the pipes. We had to call animal control and shut the whole job down for a day while they got them out safely. Has anyone else had to deal with wildlife setting up shop in gear like that?
Chewed up Romex is bad, but @casey268's story about the smell in the attic is the stuff of real nightmares... can't imagine dealing with that for weeks.
Give the wasp nest over the chewed up Romex any day. At least with wasps you can smoke them out or spray them from a safe distance and be done in an afternoon. That chewed up Romex means you're chasing hidden shorts for weeks and probably rewiring half the building.
Opened an attic hatch once and a whole family of squirrels had turned the insulation into a shredded condo complex. The smell alone was a crime against nature. They'd chewed through some old wiring too, just for fun. Took weeks to get the noise and the nut shells out of the walls.