Not quite. The four wire outlet has two hot wires (110 VAC each), a
neutral, and a ground. The older 3 wire plugs lack the ground. Even with
the 3 wire outlet, you can get 110VAC from connecting to either hot wire,
and the neutral.


Modern dryer circuits have four wires because a dryer has both a 110V
motor and controls and a 220V heating element.