Tman wrote:
Took a look at the schematic today for the dryer (240v). I've always
wondered how they serve up 240 V with 120V components (e.g. timer motor)
on only three wires.

You see, I always thought that the grounded conductor should never be
current-carrying, in the theory that if the ground feed should break,
then the metal chassis of the appliance does not get energized.

Well looks like that "3rd" wire, is a neutral, and judging by the dryer
schematic, is both used as a chassis ground and a current-carrying
conductor for the 120V items on the dryer -- such as timer and drum motor.

OK -- am I totally wrong about the code and theory, or is this unsafe?
Seems to me that dryer would get real "hot" should their be a fault in
the neutral conductor to the breaker box.

I know I'm missing something here as this is SOP as far as I am aware.
Someone please inform me?
T


It's theoretically not as safe as having separate neutral and ground
wires. But the unbalanced current is very small, the conductor is very
large, and a 240/120V 3-wire circuit is only allowed when connected to
the main panel (not a subpanel), where the ground and neutral are bonded
to the same buss.

If the neutral wire were to inexplicably come loose, I *think* the timer
relay would open and remove power to the drum motor. So the 120V on the
chassis would be current limited by the series resistance of the timer.
(I could be way wrong on this last point)

Bob