Quote Originally Posted by Washout View Post
I don't have 3 phase, so I don't think your latter scenario will apply (not yet anyway ;) ), although I was thinking of running a seperate wiring feed to the VFD (and possibly the rest of the machine's electronics) from my consumer unit (I have a spare 32A RCD), just to keep it isolated from the rest of my "stuff".
Well actually you kind of do because the VFD is converting to 3 phase.? THE BIGGEST cause of trouble with electrical problems in CNC is incorrect or bad earthing creating ground loops or electrical noise.
Very important you use Star grounding and run all earths and shielding back to this star point. That includes the VFD and it's cable shielding.
What I do is have a mains pickup point in the control box with earthing block and pick the VFD power and earth from this point but still keep it outside the cabinet.

The separate feed is a good idea helping to keep the marriage out divorce courts after the Mrs puts Air drier on just when machines at full chat 10hours into a job and POP.