How come the neutral Tee slots are solid (not cut out) if its a 20A?
As to the **** , lightning maybe.
Upon further examination, the outlet is in fact 15amp. Correction made in OP. The branch's circuit breaker is 20 amp, wired with 12AWG.
EDIT some more: I did some more garage barrel diving as I had thrown out the whole GFCI and found this label that I thought had planted the 20 amp rating in my head. I pulled another of the GFCIs from another location in shop and it had the same label but also no tee slot cutout though the tee slot plastic component of GFCI had “15a” molded into it.
I thought, disappointedly, I had 15amp outlets in 20amp protected circuits..but these stickers indicate correct rating for outlet, though with no Tee slots. What’s up with that?
Because it's a 15A duplex GFCI.
@svtride any chance this is in a metal shop?
Looks like a dead short to me. Did breaker trip?
Not a dedicated metal shop but I do some metal work at times, mostly personnel vehicle mechanical repairs and service, hobbyist, nothing commercial. Outlet is in opposite area of shop where only vehicles are stored, no work performed. Breaker had not tripped but did when I attempted to reset GFCI, BAM.
Wild guess here, but did you have any lightning storms in the area? I have seen lightning do some "wacky things" on an electrical system.
Two large storms involving lightening in recent week with a neighbor losing power (I did not) when transformer blew on utility pole that serviced his house and another.
Agree, we had a lightening strike a maple tree several years ago and over next days got whiffs of nature gas smell. Called utility, they investigated and sure enough lightening zapped a hole in gas service pipe that ran by tree to house.
