"Ivan Vegvary" wrote in message
...
My shop addition (21'x60' added on to an existing 40'x60') is coming
along.
Had to let go of my electrician due to the fact that he never shows up
etc.
He installed a new 3-phase service entrance. From said entrance we are
feeding a sub-panel to the old shop. This subpanel is single phase 100
amp.

I am to install a second 50 amp 3 phase sub-panel to another section of
the
new shop. My question is wiring for the run to the sub-panel. I purchase
some 3-#6 wire (52' run). This is 3 #6's and a ground wire. 4 wires
total.
Out of this 3-phase sub, I will be running circuits for my wife's kilns
(220v), my 3-phase machines and a few 20 amp (120v) plug circuits.


No you won't you need 5 wires and a "Y" 4 wire + ground box for the
subpanel, if you plan on any 120 volt circuits. You nay be able to get a
isolated neutral bus for your delta box from its manufacture and a new label
to put on it so the inspector will approve it

I am
confused about the 120 volt circuits. Being that I only have 4 wires (3
current, one ground), how do I run a neutral wire to these circuits. Even
more confusing is that the neutral and the ground all run to the same bus
bar, so what is the difference?

If you are confused about this, I suggest that you hire another electrician
to finish up the job.
In your case the ONLY place the grounding conductor and the grounded
conductor are to be bonded is at the service entrance.


I can give up my investment in the 52' of 6-3 cable, but I can't seem to
find any 6-4 wire (4-#6's, plus ground), at least not at any one of the
home clubs. I could simply add a fourth wire (white neutral) to the 3
phase
sub-panel, where it will simply be bonded with the ground. Or, I could
simply create a neutral by bonding to the ground in the sub-panel and not
run a fifth wire. All very confusing.

Any and all advice appreciated. BTW, I do have on older copy of the
National Electric Code, but can't seem to find the answer therein.

Thanks, Ivan Vegvary