From the ceiling come down to the machine with a piece of 4 conductor cable
sized for the machine (10 gauge for 30 amp, 8 for 60 amp) put a recpticale
on the end and come out of the machine with a 2 or 3 foot cable with a plug.
You didn't say what size machines they where (Power wise not physical size)
""PrecisionMachinisT"" wrote in message
...

"Ivan Vegvary" wrote in message
news
Getting things arranged in my new (new for me) shop. It has 3 phase
power,
therefore the questions.

1) Do I simply run 3 wires to the machines (lathe, mill, grinder &
surface
grinder) and let the conduit be the ground, or do I need a seperate
ground
wire. The existing building has a few 3ph outlets (in conduit), but no
ground wires.

2) My machines will be out in the middle of the floor. Do I simply
dangle
a
conduit from the roof framing (15 ft. above), or, do I install a post
upon
which the conduit will come down? Do I do this once for each machine?
Somebody must have a clever solution to this situation. I don't want to
cut
up my slab and install wires below.

Thanks for any and all answers.

Ivan, amateur relocated to Oregon.



Ivan,

If you like you could run a dedicated ground conductor alongside or inside
the existing conduit--bare or insulated copper should be fine..........It
then becomes your ground path--at this juncture, the conduit is simply
grounded, where this is a requirement in the case of metallic conduit
anyways.

As to the fifteen foot ceiling drop, not sure it would be to code, but if
a
plug were installed in the ceiling it would technically be a disconnect at
that point. This places the machinery into the "portable "
classification........

Personally, I would avoid running power cables across the shop floor.

The current trend is to avoid multiple ground paths.......a "star"
grounding
system is preferred, whereas all grounds lead to a central point--that
being
the service entrance grounding stake, via the entrance panel grounding
bussbar.

As such, I would recommend against pounding additional ground stakes in
the
system other than perhaps those that will be connected only to the service
panel ground buss, and only in the event the existing stake is found to be
insuffecient.

I have taken the liberty of crossposting this thread to the
alt.machines.cnc
newsgroup, as we have others there, including a resident electricial
contractor there who might well be able to answer any further questions
you
might have.

( Pinging Grampaw Lucas...........)

Cheers,

--

SVL