On Wed, 27 Feb 2008 09:04:23 -0800 (PST), rpseguin
wrote:

Ok.
Thanks for everybody's help in the earlier thread.
The 20HP rotary phase converter is working, but I now need to place it
in the garage, about 70+ feet wiring run distance from the main
breaker panel.

Given the cost of copper wire these days, my inclination is to run
just the two hots to the panel and to put a grounding rod close up to
the garage and run a local ground to it.
I see no reason to run a neutral line from the panel (the machines are
all 3 phase).

I know that I could run a ground line to the panel AND run a local
grounding rod, but is it a bad idea to just do a local ground?

What gage wire for a 20HP RPC, but the main/biggest load/machine will
be a 10HP spindle and a couple of 2HP machines, never all at the same
time? ($ signs get much bigger with the wire gage/diameter :-)

Anybody near San Jose, CA have a spool of #4 or larger gage for
cheap? :-)

Thanks in advance!

I used 6/3 SO cable for mine. For that 70+' distance however, you
might be better off with 4/3. The SO cable might cost a little more,
but it makes for a clean installation. Unless you plan to run conduit.

Also keep in mind, if you run wire instead of SO cable, your ground
doesn't need to be as big as the hot wires. A #10 ground wire will
work.

Matt