I have a new plasma torch that runs on 240v/40a. It has a three prong plug. The unit has an additional exterior threaded terminal that, according to the book, shows it to be an 'earth' connection. I purchased a Leviton three plug model 5378 250v/50a outlet. The Leviton is one end of an extension from the barn electric. It's schematic shows the the two hots and the the third shows 'ground'. I'd like to ground the plasma unit. Can I connect Leviton to the two hots and neutral instead of ground? And connect plasma torch ground (earth) to barn panel ground? The barn breaker panel does have the neutral and ground separate. In effect, the plasma torch would be plugged to two hots and neutral, while it's case is connected to ground. Would that be okay to do? Or must it be connected to two hots and the ground?