Sub panel ground

[John Gromkoski]

Am I correct that a sub distribution panel should have a grounding conductor connected to its ground bus (separate from the neutral bus) that is connected to the main panel's neutral bus?

[Joe Farsetta]

Sub panels require 3 conductors plus a ground. A separate ground bus, bonded to the panel and connected to the grounding conductor. Neutral bus is isolated from the panel case.

[John Gromkoski]

Originally Posted by jfarsetta

Sub panels require 3 conductors plus a ground. A separate ground bus, bonded to the panel and connected to the grounding conductor. Neutral bus is isolated from the panel case.

Thanks. That's what I thought.

[Robert Meier]

Originally Posted by jgromkoski

Am I correct that a sub distribution panel should have a grounding conductor connected to its ground bus (separate from the neutral bus) that is connected to the main panel's neutral bus?

It's not required to be connected to the neutral bus but if the feeder is originating at a service then the neutral and grounding bus may be one in the same.

[Joe Funderburk, CMI]

John, is the dist. panel in a detached building?

[John Gromkoski]

Originally Posted by jfunderburk

John, is the dist. panel in a detached building?

No. The main and distribution panel are in the same building. What would be the difference?

[Robert Meier]

Originally Posted by ccurrins

How about this set-up? Sub in garage. Feed from breaker at top right at service panel. Home built in 1972.

What specific problems do you see?

[Joe Funderburk, CMI]

Originally Posted by jgromkoski

No. The main and distribution panel are in the same building. What would be the difference?

If it's a detached building, there are other issues to consider. Primarily whether or not a GES exists at the building. Separation of grounds and neutrals would be different depending on whether it's a 3 wire or 4 wire feed to the building.

3 wire feeds to existing detached buildings

Grounding electrodes at outbuildings