I added an outlet to a bathroom. When I pulled the outlet, which was a 15A, that I was going to tie into it was wired with a #12. I checked the circuit and it is a 20 AMP circuit. It was part of a bathroom that was part of a GFCI. I thought maybe since the was a ground fault that it was okay to have the 15A outlet on a 20A.
I did a little more looking around comparing the circuit to the outlets. It appears that the 20A circuits are all wired with 15A outlets.
Is this a code violation or safety hazard?