I'm working in the United States. I'm looking into working with mains power, and I cannot for the life of me figure out where the ground line connects. For example, a simple power regulator from mains power: Assuming that I'm using the standard mains, there are three pins. Two are "hot", and one is "ground". I understand that the two "hot" pins carry the AC and the ground pin is used to divert current in the case of a short circuit (I think?).
I've heard people say that "ground" should be attached to the case.
Where do I solder the ground line, with a metal and a non-metal case?