[Gary Sutherland]

I have a small sub panel in a detached garage. It is grounded to the main panel which feeds it, but not to it's own ground rods.

How far from the sub panel can the ground rods be? I either have to drill through a slab to drive the rods just outside the wall the panel is on, or run the ground wire over a door opening to where there is exposed earth (about a 12' total run).

Thanks...

Gary

 

[Just Bill]

Sub panel needs its' own ground, but the neutral buss must be separate from the ground buss on the sub panel. Neutral comes from the main panel. 12' is not an especially long distance.

 

[J. V.]

Actually you may need two ground rods at the unattached structure. Don't go over any doors or have a long run of grounding electrode wire. The wire is supposed to be run in as straight a line as possible. Remember. The ground rods and wire are for lightning protection. I would want that fault to have a very short path to earth.