Local Interpretation of 312.8(3)

[BschnellECNCU]

Hello all,

I just recently joined the forum to submit a query about a recent installation that failed inspection. I have on countless occasions used this forum for code interpretation, general knowledge and many other situations to help become familiar with different opinions and resolutions to challenging electrical questions. If I’ve learned anything in this trade the past 15 years, its knowing that you will never stop learning!

On to my question/situation...


I recently completed a relatively straightforward installation of a 400 amp overhead service upgrade for a client. The existing 200 amp service became inadequate after the client added an additional 200 amp panel for a 3000 sq. Ft. wood working shop on his property. Load calculations and all are irrelevant to the main issue. Long story short- I installed a new 400 amp meter, overhead mast, etc. With 2 200 amp service disconnect/panels adjacent to eachother, and the 400 amp meter furthest to the right hand side.

The subject was brought up in this thread with the graphic that depicts my install almost identically:

Previous Thread

So install is complete and inspection is called in. The inspector comes out and fails me for 312.8(A)(3). More specifically, I labeled the feed through enclosure ”feed though conductors originate in meter enclosure and terminate in adjacent panel”. Evidently, because the code language in 312.8(A)(3) specifies “disconnect”, service conductors can not be fed through one enclosure to feed another with a disconnecting means.

Ive used this method on other installations as well, where the practicality of putting the meter in the middle just wasn’t going to work and had no problems with inspection. I discussed the issue with both the inspector and the head inspector whom both told me that this problem came up recently in a meeting and “this” was their interpretation to the problem.

Personally, I don’t understand the problem since service disconnects will always have energized conductors while the POCO meter is in place. Perhaps something that should be amended or changed for clarification in the future?

 

[augie47]

Interesting interpretation.
Awaiting Dennis' input as he is most familiar with N.C. rules.

 

[Greentagger]

Maybe their seeing the service conductors as not being “feed thru conductors”,as their source doesn’t have disconnecting means”?

 

[Dennis Alwon]

I don't see how 312.8 has anything to do with services conductors. I definitely disagree and I would call the state engineers to give an official ruling. Contact Joe Starling at the NCDOI. @augie4

 

[BschnellECNCU]

I don't see how 312.8 has anything to do with services conductors. I definitely disagree and I would call the state engineers to give an official ruling. Contact Joe Starling at the NCDOI. @augie4

Thanks for the reply,

I took your advise and reached out to Joe Starling for his opinion on the matter. I didn’t get him by phone so I sent an email and got a reply from Daniel Thomas(State Inspector).

This is his take on the scenario:



“Unfortunately, this installation appears to be a violation of 312.8 and its parts. As you may know the NEC states in section 312.8 “The wiring space within enclosures for switches and overcurrent devicesshall be permitted for other wiring and equipment subject to limitations for specific equipment as provided in (A) and (B).

In reviewing Part A it states “The wiring space of enclosures for switches or overcurrent devices shall be permitted for conductors feeding through, spliced, or tapping off to other enclosures, switches, or overcurrent devices where all of the following conditions are met (A)(3) states “A warning labelcomplying with 110.21(B) is applied to the enclosure that identifies the closest disconnecting means for any feed-through conductors.”

As part of my research for this issue I went back to see when it became part of the NEC. Actually it first appeared in the 2011 NEC. In reviewing the language for this requirement in the 2011 NEC ROP I found the following substantiation from the submitter of this proposal and also the code making panel statement in regard to this new language for the 2011 NEC.

Submitters substantiation: “Too often you can shut down the power to an enclosure with switches or overcurrent devices to comply with NFPA 70E only to find live wiring not associated with said control panel occupying the same space.”

Panel Meeting Action: “Accept the principle that energized conductors within such an enclosure and unassociated with its principal function are a potential hazard.”

Therefore, in my opinion if there is not a disconnect for these conductors, then this electrical installation is not allowed to be made as shown. This is a section that really needs a new code proposal to clear up some of the confusion that it causes in my opinion.

I hope this provides some clarity for you in regard to this subject.”



Dosent look like I’m changing any minds on this one. There again, if the intent of the code was to prohibit installations being done in this manner, than a proposal for clarification of this section is definitely warrante.

 

[Dennis Alwon]

Well, that's too bad. I still think it shouldn't apply to service conductors but I see their point. Danny was an excellent code enforcer in his days. He knows more about the Nec that I can ever hope to achieve.

 

[Dennis Alwon]

I just re-read what Danny wrote and his quote of the panel just says it agrees in principle but took no other action that I can see. I have had proposals accepted in principles but that does not mean they accept it for a ruling.

 

[Dennis Alwon]

Well I found the original proposal and Danny left out info but that just solidified his answer. I should no better than to question him. LOL Mea Cupa