# Bonding Neutral and Ground Bus



## bobward (Aug 17, 2009)

Hello All,

I am looking for a code article for backup. 

Please see the following images and PDF as I will be referencing them:
http://s21.postimg.org/cabdzky1j/IMG_1101.jpg
http://s16.postimg.org/a5f34fxdh/IMG_1103.jpg
http://www.filedropper.com/img1101edit

Preface: Main panel, GEC and Grounded conductor are bonded, due to grounds landing on the two neutral busses(they are isolated from the panel and bonded together, even though the ground is terminated there as well) the homeowner is running out of terminals to land the neutral conductors. 

Therefore, I have installed a ground bus on the bottom right hand corner of the panel. Homeowner insists on installing neutrals on the ground bus, though I have said that this is not allowed since the current from the neutral will be traveling through the box to the neutral terminal. He has then installed a ground lug on the new ground bus and a ground lug on the one of the neutral busses and is planning to run a #4AWG main bonding jumper (selected from Table 250.66) from the ground buss to the neutral bus. He is saying that this will solve the issue and will be within code and he will be able to land neutral and ground conductors on the ground bus. 

1) I need a code reference first indicating that a ground bus that is not insulated and directly connected to the panel can only accept equipment grounding conductors and no "grounded conductors"(neutrals). 

2) I need a code reference that even if he uses a "main bonding jumper" to bond the neutral and the ground bus which is directly connected to the panel that this will not be ok. 

Who knows maybe I'm off and the homeowner is on point, your thoughts are much appreciated.


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## telsa (May 22, 2015)

The Siemens factory already has the panel can set up to receive a grounding rail in the northwest quadrant. You can see the screw holes all lined up in your first jpg.

Once you've moved it over and up, it's no biggie to shift the grounding runs -- the big fat ones (#6?) onto this rail.

Problem GONE.


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## bobward (Aug 17, 2009)

Thanks for the reply. Thats a good solution but in regards to the code reference for bonding the ground bus and the neutral bus to try and be able to land neutrals, would you happen to have one? I want to present it to him for his future reference as to why he can't do it. 

thanks much.


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## don_resqcapt19 (Jul 18, 2010)

As long as this panel contains the main bonding jumper, I see no violation in what the HO wants to do.


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## bobward (Aug 17, 2009)

Thanks for the reply. I guess that makes sense as to why my scouring of the NEC could not find a violation. So te main bonding jumper is the kicker. With that that bonding the isolated neutral bus and the ground bus which is in direct contact with the box, he will be able to land his neutral wires. I guess I will make his day as to not being able to prove him wrong.


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## don_resqcapt19 (Jul 18, 2010)

bobward said:


> Thanks for the reply. I guess that makes sense as to why my scouring of the NEC could not find a violation. So te main bonding jumper is the kicker. With that that bonding the isolated neutral bus and the ground bus which is in direct contact with the box, he will be able to land his neutral wires. I guess I will make his day as to not being able to prove him wrong.


That jumper is not really the main bonding jumper....not really sure what you would call it.


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## bobward (Aug 17, 2009)

But that jumper is what makes it ok, is that what you are saying though? Because without it, objection all current will flow through the box correct?


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## bobward (Aug 17, 2009)

That is, if he lands neutrals on that bus


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## don_resqcapt19 (Jul 18, 2010)

bobward said:


> But that jumper is what makes it ok, is that what you are saying though? Because without it, objection all current will flow through the box correct?


Yes, the code clearly says you can't use the enclosure as a conductor for neutral current. The jumper between the two connection bars provides a path for the neutral current other than the enclosure.


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