Main Bonding Jumper

[bennie]

Re: Main Bonding Jumper

When there is no equipment ground wires, and the branch circuits are in metal conduit, both buses are neutral/ground buses.

The screw is the main bonding jumper.
The bond strap, link, or jumper is part of the neutral/ground circuit. Ground fault current will flow, on the link, when the screw is in the left bus to the enclosure. It will not flow when in the other side.

The point is the link has different functions according to the equipment ground terminations.

[ May 08, 2003, 02:05 PM: Message edited by: bennie ]

 

[bennie]

Re: Main Bonding Jumper

When the equipment ground conductors, system neutral, and electrode conductor, are all connected to the same terminal bus, there is no main bonding jumper.

[ May 08, 2003, 03:27 PM: Message edited by: bennie ]

 

[david]

Re: Main Bonding Jumper

?but this panel also incorporates a factory provided main bonding jumper that would connect the neutral bus to the equipment enclosure via a bonding screw?

?The only point that I am trying to make about this particular panel is that this piece of metal is serving two purposes; one of those being the connection of the grounded service entrance conductor to the equipment enclosure?

250.24 Grounding Service-Supplied Alternating-Current Systems.
(A) System Grounding Connections.

(4) Main Bonding Jumper as Wire or Busbar. Where the main bonding jumper specified in 250.28 is a wire or busbar and is installed from the neutral bar or bus to the equipment grounding terminal bar or bus in the service equipment, the grounding electrode conductor shall be permitted to be connected to the equipment grounding terminal bar or bus to which the main bonding jumper is connected.

Since the bonding jumper from the neutral bus lands on a bus bar strap that connects to the second bus bar and the second bus bar is bonded directly to the tub I believe 250.24 (A) (4) applies.


David