Quote Originally Posted by kenwhite View Post
Wade, you do inderstand most of it.

The 240 VAC load does not use a common, it uses 2 hots that both see the same current through them, and a safety ground that does not see any power current unless there is a fault.

If you look at the load as a constant power, where voltage x current = power, you can see that when the voltage is doubled, the current through the line is reduced to half.

Since current through the line is the primary limiting factor when sizing cables, a 240 VAC branch can use a larger AWG, smaller diameter, cable for the same power load.

Cables and breakers are sized by the National Electric Code (NEC).

Oh, the reason a Dryer connection uses 4 wires -> 2 hots, a common, and a safety ground, is because it typically needs 240 VAC for the heating element and 120 VAC for the control, sensor and lamps.
Thank you Ken that confirmed what I always thought, One last qestion, I think I read something posted by Mark saying that the duty cycle of the machine affects the size of the power cable you can use to it..I.E. higher AWG, (Smaller Diameter) knowing the machine will have to rest. and would this apply to a breaker as well? I am just wondering how Griz is able to get away with a 30 amp breaker with his 250ex. I think he started this whole debate.