What is the specifications on the machine? What and where does the plant exactly need this equipment?
I believe there are some real design considerations.
It will never be a case of down sized the conductors because you?ll need to upsize the wire to maintain the desired voltage at point of use.
Depending on the size of the plant, my thought is that you will need multiply circuits not one circuit, one should certainly do a voltage drop calculation if you try to do a single circuit. Yes you could run a circuit out and split it into two individual connection points for an area of the plant, then do the same again from another circuit. This to me would be my maximum for a circuit. If you were to split the circuit use a directional indicator to transfer power so that two welders aren?t used at the same time on this one circuit, just something else to consider.
Here?s the numbers; say the machine has a draw of 12 amps, w-6 AWG, you limited to 200? (one way circuit length) ((remember this is a total linear run- up, down, across and sideways)), and maintain less than a 2% voltage drop; 8 AWG gives 3.2% VD.
Try your own voltage calc's.
Here
IMO, One will use some pretty big wire if you did just ?one? circuit and daisy chaining your service forward into the plant.
Of course all this depends on the power source(s) in the plant and point of usuage.
Sounds like a fun project, Enjoy!