BOB\Driver crashing? on CNC Plasma table.

[JAZZCNC]

What should I be looking for? I need 4 core shielded, but how "big" or "small"? Is bigger better or detrimental?

1.5mm/2 for steppers and for signals to drives, limits etc then 0.75 or0.5mm/2 will be enough. You could also use shielded Cat5 cable which as 8 wires in twisted pairs which is good to use in the control box to cut down on wire runs.

I'll be taking the opportunity to relocate the PC and drivers etc. further away from the table so this is all a good thing :-)

Don't go crazy on the length keep it to the minimum you need.! . . . Long wires mean longer more receptive/conductive antenna.!!