Multiple equipment grounding terminal bars in a single panelboard

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cdcengineer

cdcengineer

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The question came up how to connect multiple equipment grounding terminal bars in a single panel. The first terminal bar was factory installed. I would think that by screwing the second terminal bar (catching two threads on the panel interior surface where paint has been removed) would be acceptable, but a local inspector wants a conductor run between the two bars.

Thoughts and input are greatly appreciated.
 
tkb

tkb

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Location
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I don't think it is required but I usually connect them with some #6.

Just do it and be done with it.
Be smart about the battles you pick with the inspector.
 
cdcengineer

cdcengineer

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This is a 1200A distribution board. Not sure if the enclosure would act as a suitable bonding jumper. Perhaps they would need to connect with a conductor sized per 250.102(D).
 
tkb

tkb

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cdcengineer said:
This is a 1200A distribution board. Not sure if the enclosure would act as a suitable bonding jumper. Perhaps they would need to connect with a conductor sized per 250.102(D).
Click to expand...

That is a little different situation than what I was thinking.
The jumper would have to be 3/0 CU for a 1200a OPD as per Table 250.122.

Unless you can prove the enclosure is suitable for use as an equipment ground. It may be suitable, but it is hard to prove.
 
Smart $

Smart $

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tkb said:
...

Unless you can prove the enclosure is suitable for use as an equipment ground. It may be suitable, but it is hard to prove.
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Wouldn't have to if the second grounding bus is a listed add-on for the panel and the instructions only require attachment to the enclosure.
 
Dennis Alwon

Dennis Alwon

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If this were a main panel that was the ungrounded and egc bar then you would need a wire or some connection between the bars. If it is a straight egc bar then no wire is needed.
 
cdcengineer

cdcengineer

Senior Member
Dennis,

This is not a main panel - no GEC. The grounding terminal bar is for EGC's only. The argument is that the multiple terminal bars must be connected with a equipment bonding jumper. NEC requires that bonding jumpers material be of copper or other corrosion resistant material. I am not sure if Eaton's panelboard's would be considered corrosion resistant.

Good feedback so far - thanks
 
Dennis Alwon

Dennis Alwon

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I look at like this. You don't need a bonding jumping on the emt that may be attached to the panelboard so why would you need it for the other egc bar.
 
cdcengineer

cdcengineer

Senior Member
The grounding terminal bar is not part of a listed assembly from the manufacturer per Smart $'s comment, but still I agree with with Dennis.

And it's not about arguing with the inspector. It's about saving people money by not enforcing requirements which are not dictated by code.

Thx
 
Dennis Alwon

Dennis Alwon

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tkb said:
The OP stated that it was for a 1200 amp feeder.
Click to expand...
That does not mean I need 3/0 between the bars. I can have the 3/0 to the first bar and then branch to the other bars based on the largest size conductors on those bars-- NO?
 
cdcengineer

cdcengineer

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The panel in question is served with 1200A. The largest feeder from this panel has a #3 CU EGC. Either way, I don't see why it would be necessary to connect the 2nd bar via conductor.
 
kwired

kwired

Electron manager
Location
NE Nebraska
tkb said:
I agree, but is it worth arguing with the inspector over 5' of 3/0?
Click to expand...

What if the bar only accepts #4 as the largest conductor? I mostly install Square D equipment and they have an adapter lug for a larger conductor but it would only accept 2/0 max.

Dennis Alwon said:
That does not mean I need 3/0 between the bars. I can have the 3/0 to the first bar and then branch to the other bars based on the largest size conductors on those bars-- NO?
Click to expand...

Works for me. You are not bonding the panel if the EGC from the supply is not landed in this bar, you are bonding whatever branch circuit or sub feeders EGC's are attached to it.



You could also use the panel cabinet plus a metallic raceway as the EGC to a junction box immediately adjacent to the panel and mount the ground bar in there and continue with a wire EGC and it is not questionable - it is allowed, yet you have more possible connection points that could introduce impedance into the EGC path.
 
tkb

tkb

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Location
MA
cdcengineer said:
The panel in question is served with 1200A. The largest feeder from this panel has a #3 CU EGC. Either way, I don't see why it would be necessary to connect the 2nd bar via conductor.
Click to expand...

Just to be clear, I don't think it is necessary either.
I was just suggesting to appease the inspector with an minimal cost because it is not a large or worth the fight.
 
infinity

infinity

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What code section would be violated if the multiple equipment ground bars were connected only by the metallic cabinet?
 
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