Quote Originally Posted by Ken Sully View Post
I agree with Jim.
I you have two different grounds you will end up with dissimelar grounds and current can flow between them. Make suer your system is tied to the same ground. Not one from the house and one from your ground rod.
Well this is all pretty overwhelming, particularly for someone who knows diddly about electricity.

The only ground rod I am aware of in my shop is the one the electrician drove into the ground through the concrete. Isn't everything else grounded via the third prong of a plug right into the electrical system of the building?

Isn't the ShopBot grounded simply by being plugged into its 220 outlet? I don't have any additional copper wires going from the machine to a ground. Never have.

If I disconnect the copper ground wire that currently runs from the DC frame to the ground rod, how do I ground the DC? (It's an Oneida Gorilla Pro, and it came with a ground wire that runs from the top of the motor and clips to the metal mesh frame around the filter, which has always been attached). Run a copper wire from the metal ductwork to electrical conduit on the ceiling?

The DC is literally a few feet from the ShopBot. Does that make the problem worse?