I understand from reading about noise issues that you earth a shield at one end only to avoid ground loops.Do you need to worry about ground loops created when earthing themachine for safety purposes? For example, if I earth the machine frame and I earth the spindle body, does this create a ground loop (because the two are connected) and is this an issue? Would I be better off with one earth and then ensuring conductivity between all parts of machine?

Also, should a BOB be earthed (currently powered by an old phone charger with only two wires)? And should my PC earth be connected to the main earth point for everything else?

Many thanks for any replies as always.