Bonding Neutral And Ground In A Sub Panel

The ground and neutral must be bonded only at one place in the main panel to avoid this.

Bonding neutral and ground in a sub panel. The bonding for the main ground sources such as a ground rod is made at the main panel where all the grounds are bonded together as well. A main breaker on a sub panel is not necessary because this is in the same building if you are in a different building then nec 22531 22532 22533 apply. In some cases the metal conduit might be a proportionally better path than the neutral wire feeding the sub panel and the majority of the neutral current could then flow on the bare conduit. That said having a main breaker in the sub panel is also acceptable.

Any info would be greatly appreciated. Ground neutral and hot wires explained duration. I consider it best practice to always provide a ground wire inside metal conduit but there are probably millions of installations that rely on the metal conduit as the path back to the service equipment. There is no bar connecting the 2 buses.

The panel is a ge powermark gold load center 100125amp. One person told me you can screw the green ground screws 1 through the neutral and 1 through the ground buses into the back of the panel box and that is how the box was designed. Bonding on a sub panel if you ground the neutral at a sub panel all the bonded water lines conduit metal appliance enclosures and anything else metal that is bonded becomes a parallel return path. If you bond them anywhere other than the main service the neutral return current now has multiple paths including though your ground wire.

In this case the current from a ground fault goes through the egc within the garage back to the sub panel in the garage and via the continuation of the egc back to the main panel in the house. This is a brief walk through of a simple grounding and bonding system and what happens with the flow of current in normal operation and in a ground fault condition. The sub panel ground should not have a ground rod tied to it. They should only be bonded at the main service panel.

The sub panel neutral bar or terminal should not be bonded to the enclosure or the ground of the sub panel. If you run an egc to the garage reference nec 25032b1 you dont bond neutral and ground at the garage panel. What is a neutral bonding screw in a main or sub panel load center should it be used or removed. The neutral and ground must not be bonded at a sub panel.