What if no separate ground wire in plug? Answered
I'm in the US and, generally speaking, comfortable with the AC wiring of my house. At the wall outlet, black is hot, white is neutral, and green (or bare copper) is ground. As preliminaries for this class, I am building a variable power switch for my soldering iron, using a standard metal box, standard electrical receptacle, and a slider switch. If I connect the switch-and-receptacle-in-a-metal-box to the wall using a cord with only 2 prongs (i.e. no ground prong for the wall), do you see a problem connecting the ground to neutral in the metal box holding the receptacle & sliding switch? Since all the ground and neutral wires connect to the same bus inside the main panel on the side of my house, I can't imagine why connecting the ground and neutral earlier, in the metal box, would be a problem.
... Come to think of it, I generally followed the locally approved practice of having up to 3 circuits use the same neutral wire, and up to 3 circuits use the same ground wire. I don't know if that would make a difference.