Neutral Bussbar in Service equipment

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hurk27

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Portage, Indiana NEC: 2008
We have a New AHJ in a small town we have been doing work in for a while. He keeps insisting that there has to be a grounding busbar installed anytime N/M type wireing is used because of artical 408.20. He is not red taging us yet as he is not sure about it ether but has asked me to provide a explaination as to why 408.20 does not have to be followed. I have never come accross this question before and after reading it I can see his dilima. But I think the anser is in the last paragraph of the artical (in bold):

Grounding conductors shall not be connected to a terminal bar provided for grounded conductors (may be a neutral) unless the bar is identified for the purpose and is located where interconnection between equipment grounding conductors and grounded circuit conductors is permitted or required by Article 250.
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Is there anything else that I can point out to allow him to understand this?

I also brought up the requirment that grounding conductors and gounded conductors are only required to be kept seperate when the service disconect is located ahead of this panel. But he seems to understand this and said it wasn't about keeping the wires seperate, it was about what 408.20 was requiring. But I need to reply to him soon before he starts beliving this and starts red tagging.
Any help on how to explain it will help.
Thanks Wayne
 
Re: Neutral Bussbar in Service equipment

I asked a very similar question here:

This Thread n

I would get the panelboard manufacturers instructions and/or specifications to see if they identify the grounded conductor terminal bar as being permitted to be used for the equipment grounding conductors. I know the newer ITE panelboards specify the grounded terminal bar for use as an equipment grounding terminal bar if the connecting bar is removed and the "reidentified" terminal bar is bonded to the enclosure.
 
Re: Neutral Bussbar in Service equipment

I'm printing out the Info as I type on the Siemens load centers. But the instruction only requires that the jumper bar be removed if the load center is not going to be use as service equipment. (as in a sub panel) but when it is used as service equipment with the main breaker using the suppled grounding conductor lug the neutral bar can be used for both as per there instruction. I have tried to find similar on Square D's web site but to no avail I came up empty. We use the Siemens panels and it was these panels that was in question. I have just never had this before and want to respond in a more educating type of response and not a "well I always done it this way response" The inspector is very nice and seems to want to work with us as he is also an electrician as well as a IAEI member as we go to the same meetings ( the same one that Glen Z. also attended) and seems to want to follow to the letter of the code as well. which is great as we need this in our area. as we do have some that want to write the code as they go. But I just want good way of applying it so as to not upset the ability to work together.
 
Re: Neutral Bussbar in Service equipment

I believe that 250.24(A)(5) permits this type of connection on the line side of the service disconnect, which is the example you have presented. I also believe the manufacturers will permit this with their equipment that is suitable as service equipment.

Pierre
 
Re: Neutral Bussbar in Service equipment

This is one of the codes that I have listed to show him and a few that require that fault current must have a low impedance to fault the OCPD. by using the neutral bar as the grounding bar too this removes a few more connections that could go bad. Ie. the grounding bar to case connection. and would be a much better connection.
Thanks
 
Re: Neutral Bussbar in Service equipment

If he read the whole two paragraphs this would not be an issue. Have youever seen a panel that does not allow the neutral bar to be used for equipment grounds? I have not. I beleive the Seimens panels state that unused terminals on the neutral bar can be used for equipment ground conductors. I think this info is right on the panel itself. He is wrong.
 
Re: Neutral Bussbar in Service equipment

Square D's load center installation instructions say to wire per local codes. No mention of where to put wires.

But page 9 of their loadcenter catalog spells it out in detail:
"All unused neutral terminals may be used to terminate bare or green equipment grounding conductors when the load center is used as service equipment".
 
Re: Neutral Bussbar in Service equipment

Our local AHJ red tags us for doubling up (two conductors under one screw) grounded and/or grounding conductors on the bussbars. Due to this, I have gotten into the habit of installing seperate grounded and grounding bars just to stay out of trouble.
 
Re: Neutral Bussbar in Service equipment

While you are not allowed to double up grounded conductors your are permited to double and even tripple up grounding conductors if allowed by the manufacturer. All brands I use allow it. I would ask for an explanation and specific code rule from the ahj.
 
Re: Neutral Bussbar in Service equipment

Scott Where is it permitted in the code that you can double up the bare grounds? The code only allows this as far as I know in 110.14 (A) where the last sentence says you may only do this IF the terminal is listed for that purpose ie: more than one wire. Is there another code section that you know of that permits the grounding conductors to be doubled up?
 
Re: Neutral Bussbar in Service equipment

Stew, that is what he is talking about. The bar is listed for 2 or 3 grounding conductors but not grounded conductors in the same hole. :D
 
Re: Neutral Bussbar in Service equipment

Ok Here's what happened at the IAEI meeting:

The inspector that was questioning this brought it up and most of the other inspectors were arguing that the only reason this was in the NEC was not to allow the neutral bar to be used for grounding conductors. :confused: I stayed my ground and even asked them why then is there an allowance if the bar is identified for this purpose. They didn't seem to have an answer. :confused: Many reasons why this should not be allowed flew around, Like if the bonding screw was ever removed or the neutral connection was lost. but each time I was able to show them how these reasons was wrong. Then finely I gave them the idea that it seems that the only reason I could figure 408.20 was put in the NEC was because of some manufactures will only have enough terminals to allow each neutral it's own terminal. Like in the case of a T&B load center, A T&B panel that has 20 breaker spaces will only have 20 neutral bar terminals. And if this panel is installed without a grounding bar (with NM ran for circuits) (If all the circuits was not used) then someone adding circuits at a latter date will have to double up neutrals to make room for the new circuits. And After looking at the label inside of a T&B panel today I didn't find the statement that says the "unused neutral terminals can be also used for grounding conductors" That all the other major manufactures say.
And the fact that most of these other manufactures will have double the amount of neutral terminals than needed.

After this most started agreeing with this and sounded like they understood but a couple didn't and stood firm to the " it wasn't allowed" Idea.
One of these was our secretary to our IAEI and I think Charlie knows him and maybe could e-mail him for me? But I'll leave that up to him as he did say he was going to check into it more when even our president stood on what we discussed and agreed with what I presented. They are a great bunch of guys but can be stubborn at times.
And as far as this inspector red tagging for this he aggreed with me after what I presented and said unless he hears anything offical it's mute.

Thank's for all the help everyone.
 
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