The 220 recepticle was put in by a licensed electrician. Looks like the wire is orange romex that says "awg 10 grounded type nm-b."
To be honest I'm not sure what type of plug this is. It's only a 3 prong plug. Two flat blade prongs at an angle and a third in middle (triangle formation) that is "L" shaped."
Without getting into the panel, is there a way to tell if the L shaped prong is a ground or neutral? Or just in general to tell is a wire is grounded?