3 Answers. The neutral and ground MUST NOT be bonded at a sub-panel. They should only be bonded at the main service panel. If you bond them anywhere other than the main service, the neutral return current now has multiple paths, including though your ground wire.

Do I need to run a ground wire to my sub panel?

The neutral and ground cannot be bond at a sub-panel. The main service panel is where they should be bonded. ... The sub-panel ground must be connected to the ground wire from the house. The ground rods should be tied to the sub-panel ground since it is a detached building.

How do you ground a subpanel?

Rule #3: In a subpanel, the terminal bar for the equipment ground (commonly known as a ground bus) should be bonded (electrically connected) to the enclosure. The reason for this rule is to provide a path to the service panel and the transformer in case of a ground fault to the subpanel enclosure.