petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Can the bus bar that is allowed to be used as part of a GEC also be used as a connection point for EGCs?
Can the bus bar that is allowed to be used as part of a GEC also be used as a connection point for EGCs?
In most cases that would run into a problem with 300.3(B).
but there are cases where the bus bar could be located somewhere that it would not violate this provision.
250.130(C) Nongrounding Receptacle Replacement or Branch
Circuit Extensions. The equipment grounding conductor
of a grounding-type receptacle or a branch-circuit extension
shall be permitted to be connected to any of the following:
(1) Any accessible point on the grounding electrode system
as described in 250.50
(2) Any accessible point on the grounding electrode conductor
(3) The equipment grounding terminal bar within the enclosure
where the branch circuit for the receptacle or
branch circuit originates
(4) For grounded systems, the grounded service conductor
within the service equipment enclosure
(5) For ungrounded systems, the grounding terminal bar
within the service equipment enclosure
That'd be okay for an SDS, second building/structure situation, and ungrounded systems, but not for grounded-system service equipment. The GEC is required to be connected to the grounded service conductor and thus on the grounded conductor side of the MBJ. EGC's must be connected to the other side of the MBJ. I realize enforcement is quite lax in resi' service panels... but may not fly in commercial/industrial.suppose the GEC bus bar was located inside of an MCC or a panelboard.
suppose the GEC bus bar was located inside of an MCC or a panelboard.
Common GEC to GEC taps, EBJ connection, and redundant grounding....
Just wondered what it is supposed to be used for.
EGC's must be connected to the other side of the MBJ. I realize enforcement is quite lax in resi' service panels... but may not fly in commercial/industrial.
Not explicitly... but it is inferred (...and I do not mean implied).Is that stated in the code?
In the strictest interpretation of Code text, yes.So its a violation to land an EGC on the same terminal bar is the grounded service conductor?
Not explicitly... but it is inferred (...and I do not mean implied).
Here, I'll help you notice...Oh boy, hold on while I research the difference between "inferred" and "implied" :dunce: :?
I was a math major not an English major.....Interesting technicality I never noticed.
Grounded conductor on one side of an MBJ and EGC is on other.Bonding Jumper, Main. The connection between the
grounded circuit conductor and the equipment grounding
conductor at the service.
Here, I'll help you notice...
Grounded conductor on one side of an MBJ and EGC is on other.
Is an MBJ required at the service disconnect of a grounded system? Yes.
Can you connect an EGC directly to the Neutral bus in service equipment? By definition, the EGC would be connected to the wrong side of the MBJ.
As far as the NEC is concerned, there is no other arrangementI think the problem is that the NEC assumes that there is a separate "neutral bar" and "ground bar" and the ground bar is electrically attached to the enclosure. The wording doesnt really account for other arrangements.
In this case, the green screw is just a bonding jumper, not the main bonding jumper. Choose your monikers wisely...Take your typical residential panelboard and I guess you could land the neutrals on one side, the grounds on the other and call the factory connector between the two sides the MBJ, but then you have a second MBJ - the green screew to pick up the enclosure.
I have not heard of any rejections for using a supplied ground bar or one that's a listed accessory where not supplied. It's only where not within a listing that an installation is more readily scrutinized and open to interpretation.I suppose the super correct way to do it is to land the EGC's on ground bar, install a MBJ between it and the neutral bars, and throw away the green screw......
Here, I'll help you notice...
Grounded conductor on one side of an MBJ and EGC is on other.
Is an MBJ required at the service disconnect of a grounded system? Yes.
Can you connect an EGC directly to the Neutral bus in service equipment? By definition, the EGC would be connected to the wrong side of the MBJ.
Me, too!Interesting, I wonder if the intention in the definition is to call the panel enclosure the equipment grounding conductor.