On 12/8/09 6:06 PM, "dpb" wrote:

Leon wrote:
...


Code... hmmmmm. Naw there was no ground at all in the box that I spliced
into. ;~) The dryer and shop share the same circuit. If I ever move I
will yank the external addition.

I bet there is...(a ground that is)...

If it's 3-wire dryer outlet the "neutral" will actually be on the ground
connection conductor...so when you tied your third to it it is also
ground. I'd wager that's what you'd find if you were to check the
circuit connections in the panel.

Neutral is connected to an earth ground at the service panel but the neutral
and ground wires play different roles in the circuits once you leave the
main panel. The neutral carries current. It s nominally the return path, but
because we use AC, the current flows in both directions at different times.
The ground should never carry current in normal situations. It is there for
protection.

In a three wire 220v set up, you have two hot wires and a ground. The two
hot lines are in opposite phase, giving the 220v volts.

If you are re-wiring a tool to run on 220, you should also change the plug
to one rate for 220. They have a different prong pattern so you can't easily
plug them into the wrong circuit.