When Should Grounds & Neutrals Be Connected in a SubPanel? The answer is never. Grounds and neutrals should only be connected at the last point of disconnect. This would be at main panels only.
Should neutral and ground be bonded?
A high-resistance reading (typically greater than 200 ohms) indicates that there are no metallic paths between the panel and the transformer, and therefore a neutral-to-ground bond in a grounded system is required.
Should a sub-panel be bonded?
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.
Why does the neutral and ground have to be separated at the sub-panel?
With ground and neutral bonded, current can travel on both ground and neutral back to the main panel. If the load becomes unbalanced and ground and neutral are bonded, the current will flow through anything bonded to the sub-panel (enclosure, ground wire, piping, etc.) and back to the main panel. Obvious shock hazard!
Are neutral and ground tied together at the main panel?
At the main service panel, the neutral and grounding wires connect together and to a grounding electrode, such as a metal ground rod, which is there to handle unusual pulses of energy, such as a lightning strike. This is the only point at which the neutral connects to ground.
Does a subpanel need a separate ground rod?
Yes, any sub panel outside of the main building requires it’s own ground rod and a ground wire back to the main building. And yes, a sub panel in the same building as the main does not need a ground rod – only the ground wire.
Where do you bond your neutral at a service?
In simple terms, the only place we want to bond the grounds and neutrals together is in the service equipment. Many people refer to it as the “main panel” or a variety of other terms. Regardless of what you may improperly call it, the point where you can disconnect all power to the building is the service equipment.
