The mains is of 3 wires, live. neutral and earth, the earth going to the utility pole as well.
I did run a separate earth metal rod, because it said in the vfd manual to avoid having the same ground with a welder, and I do weld quite a bit these days.
From what I understand so far, I.ll unite all shieldings from all components in the utility box, and only at that end, and run everything into an earth, be it back in the mains or the metal rod.
If I got it right, I.ll do so in the next days and come back with the results.

Thank you.