GEC bus bar

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iwire

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Massachusetts
but there are cases where the bus bar could be located somewhere that it would not violate this provision.

Cant imagine many.

But in my opinion the only time you could do what you are suggesting is when using 250.130(C)(1)


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
 

Smart $

Esteemed Member
Location
Ohio
suppose the GEC bus bar was located inside of an MCC or a panelboard.
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.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
The reason I asked is that we do some work with aluminum structures used to house control panels and such.

They often come with a bus bar. I have often wondered what it is for. It can't be used as a tie point for internal EGCs as it would violate the code as pointed out above.

It seems like the only thing it could be used for is as a GES bus, but it does not appear to me that a copper bar can be part of a GEC unless there are multiple SDS and there is a single GEC that they all tap to.

Just wondered what it is supposed to be used for.
 

Smart $

Esteemed Member
Location
Ohio
...

Just wondered what it is supposed to be used for.
Common GEC to GEC taps, EBJ connection, and redundant grounding.

Where I have run into those mostly are industrial, some commercial facilities with distribution and controls dog-houses.

Where an installation is NEC compliant, there is no need for them. But the NEC establishes minimums, and some (many, most, all... ;)) engineers have to flex their purpose.
 

GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
To infer is to make a finding of fact from a set of indirect or fuzzy statements.
To imply is to strongly suggest an idea without directly stating it.
Logical implication is rigorously correct although perhaps not obvious. Conversational or rhetorical implication is less rigorous and may intentionally misleading.
So if I make a statement implying something, you could hear that and infer from my statement what I was implying. :)
 
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macmikeman

Senior Member
EATON 20/40 circuit meter/main enclosures. Poco here does not allow gec into the left (before the main disconnect breaker which is on the right side of the can and separated by a metal divider.) We run the gec to the busbar on the right side of the can, which is connected to the grounded conductor in the left side of the can by a busbar running from the left side to the right half of the can. The same busbar allows connections of grounding conductors to be landed on that busbar per the printed labeling on the cover of the can. So... it is either that maker has the code wrong and has sold a lot of violation cans, or the manufacturer instruction overrides the code regarding this . Next one I hang I will shoot a photo to show what I mean about the bus and connection to the grounded conductor . Wait, I found one.
3346-image.jpg the lug at the top is for one of the ungrounded , the larger lug on the left on that slanted busbar is the grounded conductor connection. The small lug with the green 10-32 screw I pulled from my pouch to add a bonding jumper to a bonding bushing on the rigid steel underground lateral riser coming into the socket from the poco pullbox in the sidewalk . That bus goes over to the ''customer side of the can, as I described earlier.
 

Smart $

Esteemed Member
Location
Ohio
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.
Here, I'll help you notice... :D
Bonding Jumper, Main. The connection between the
grounded circuit conductor and the equipment grounding
conductor at the service.
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.
 
Here, I'll help you notice... :D

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.

I 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. 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 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......
 

Smart $

Esteemed Member
Location
Ohio
I 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.
As far as the NEC is concerned, there is no other arrangement

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.
In this case, the green screw is just a bonding jumper, not the main bonding jumper. Choose your monikers wisely... :p

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......
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.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Here, I'll help you notice... :D

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.

Interesting, I wonder if the intention in the definition is to call the panel enclosure the equipment grounding conductor.
 
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