In article . net, RoyJ says...

Sorry, the safe way to do this is to run the green or bare wire all the
way through from the main box to the sub panel to the VFD to the Lathe
to make sure all are at the same potential. then fix your ground loops
as seen by the VFD. I doubt if you will have any troubles, VFD's are
designed to work in some very ugly environments.

As I said, it would not hurt at all to have a green wire go all the
way from the machine, to the VFD, to the sub-panel, and back to
the service entrance.

Many local codes allow the conduit to be used as the grounding
conductor. Because he does not have a green wire all the
way back to the service entrance, his green wire would stop
at the sub-panel - unless he continuted it on to the service
entrance.

This is probably how I would do it, personally.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================