Elmo wrote:
On Sun, 25 Jul 2010 05:46:47 -0700, Jon Danniken wrote:
Find out if your compressor expects the third terminal to be a ground;
the third wire on your dryer is likely a neutral. If such is the case, you
will need to install a properly grounded outlet for your compressor.

It's a ground that shares neutral function, not vice versa...

Isn't a ground for the compressor NEMA 6-20P plug the same as the neutral
for the dryer NEMA 10-30R receptacle?

Yes, addressed elsewhere...

As to sharing the receptacle between a dryer and a compressor

Actually, I should have mentioned, there is no sharing. There is no dryer
on this spare receptacle in the garage. ...

In that case, the simple (and relatively inexpensive) solution would be
to swap to a 20A breaker to support the proper 20A outlet style to plug
the compressor in directly. There's nothing wrong w/ the wiring being
_larger_ than required for the ampacity of the circuit; all it does is
mean there will be even less voltage drop than otherwise would be.

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