No it wasn't powered when hung up. I think maybe internal piece broke later causing arcing or something. In other outlet in kitchen when I plugged it in the final time it shot green spark and tripped gfci.
I just moved a wall electric outlet from the side of the wall to the adjacent closet wall. Basically I pulled the walls through a 6 inch wall and mounted a new outlet box. This is all so I can hide wires on flat screen tv. Any who, when I was putting tv back on mount it made a weird plastic loud...