jamesgangnc wrote:
...

Yes, the L shaped prong is the nuetral on a 3 wire dryer. The other
two are the hots. ...

It is ground serving (per applicable Code of the time) as ground/shared
neutral.

Your compressor more likely needs 2 hots and a
ground. While what you are doing is not exactly by the book it will
run your compressor.

It is _exactly_ by current book for 240V service w/ the 240V load there
is no need for the neutral; therefore the ground is no longer serving as
a shared neutral only as ground.

The safety issue is that you will be using your
nuetral line for a ground and using a 30 amp circuit where a 20 amp
one is called for. What you really need to do is install a dedicated
220 outlet in the location of your compressor. Have you looked at the
compressor to see if it can be run on 110? Many motors have alternate
wiring that allows them to run on 220 or 110.

No, NO, _NO_! There is no safety issue; as above the 3rd conductor in a
shared utility (dryer) outlet _IS_ the ground conductor; the NEC
formerly allowed it to be shared function of also serving the neutral.
It is wired to the ground bus, _NOT_ the neutral.

The second misconception here is that there's some proscription against
a higher-rated circuit supply a lesser-rated load--that again is simply
nonsense. The 30A circuit breaker/fuse is there to protect the circuit,
_NOT_ the load; the load will have its own overload protection for that
purpose.

While I'll agree it's certainly a nuisance factor to have a humongous
30A dryer plug on the end of the cord for a small compressor, it is not
an issue whatsoever from a safety (or Code, for that matter) standpoint.

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