400A Service - Remote Meter Location

[George Stolz]

Radio, I believe Don is saying we can have several sets of service conductors, there's no need to try to call a group of conductors a "set" at all.

 

[radiopet]

I think the text "3-wire" in this section is referring to a system, as opposed to an actual conductor count.

The NEC is replete with "single-phase, 3-wire" and "three-phase, four wire" references.

Thats what I was thinking....until I was told it does not apply.....originally I informed the guy that I felt 310.15(b)(6) would apply and be fine....

I felt it would be a GREAT topic to field questions...i do think the wording Service Entrance Conductors in the opening statement allows this......but I can SMELL revision...lol.....

 

[don_resqcapt19]

radio,

So you see two sets of lets say (3) 4/0AL conductors with (3) in each raceway to each 200A panel as being a single SET of Service Entrance Conductors in the application of 310.15(b)(6)

No I see it as two sets, but I see no limit on the number of sets that can be used in 310.15(B)(6).
I also agree that the "3 wire" wording applies to the system and not the number of conductors.
Don

 

[radiopet]

I will let this die...I am being told I am wrong....by higher ups than me...saying 310.15(b)(6) does not apply to multiple sets of Service Conductors so i will leave it alone.

I know the local AHJ will allow it so I told the guy he is fine......I have lost the drive to debate this now since I am told I am simply wrong.....

Actually i started this out to help the AHJ and GUY understand.....originally I felt 310.15(b)(6) would not apply in his application...then I felt it would apply...now I just dont know.....

I am told it is CLEAR CUT......not allowed......so i give up as I must be wrong and will leave it at that and tell him to run 3/0 CU....

 

[George Stolz]

I will let this die...I am being told I am wrong....by higher ups than me...saying 310.15(b)(6) does not apply to multiple sets of Service Conductors so i will leave it alone.

Keep fighting, Radio! What are they gonna do, red tag you?

originally I felt 310.15(b)(6) would not apply in his application...then I felt it would apply...now I just dont know.....

By all rights, it shouldn't. I think it was an error when they wrote it. Something about a sentence 59 words long with 9 commas (if memory serves), it probably got lost in the shuffle.

I am told it is CLEAR CUT......not allowed......so i give up as I must be wrong and will leave it at that and tell him to run 3/0 CU....

I'd say solid advice would be to run 3/0 to avoid a scuffle. After things have simmered down, you might take somebody out to coffee and go over the enforceability of a thumbs-down on 310.15(B)(6) for that case.

How many AHJs are wrapped up in this discussion?

Edit to add: Looks like I need to revise my picture on this. The picture is right, but it looks like I need a second one to cover a single residence's service conductors.

 

[radiopet]

George,

Actually I was called by the AHJ to help clarify it...was not my job actually...

His point was both cost and requirement...obviously...if the guy could install (2) Sets of 4/0 Al USE....lets say...it would cost a huge amount less than him running 3/0 CU...for the 75'

So this is kinda where it started......

Personally i felt the conductors were protected fine and not really a issue if it is considered a 3 wire setup....as 2/0Cu or 4/0AL is allowed under the 310.16(b)(6)...and considering frankly since 4/0AL is rated for 180A and can legally be placed on a 200A OCPD....did not see a problem in giving him my view on it....

But then....was told it was VERY clear...and i did not feel it was clear....the higher up I was speaking about is NOT a AHJ...lol

 

[ryan_618]

I missed this thread and was then e-mailed about it. Right now, I agree with Don, there is no limit on how many feeders this table allows. I beleive this is because of the the fact that there is a parenthetical "S" on the words feeder(s) and panelboard(s). There is a 2008 proposal that is passing, however, to delete the "s" from both, thereby implying that the feeder can only serve 100% of the load, otherwise 310.16 would have to be used.

6-61 Log #194 NEC-P06 Final Action: Accept in Principle

(310.15(B)(6))

Panel Meeting Action: Accept in Principle

Remove the 2 sets of parentheses and the duplicate ?s? on panelboards so that the section reads:

6) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders. For individual dwelling units of one family, two-family, and multifamily dwellings, conductors, as listed in Table 310.15(B)(6), shall be permitted as 120/240-volt, 3-wire, single-phase service-entrance conductors, service lateral conductors, and feeder conductors that serve as the main power feeder to each dwelling unit and are installed in raceway or cable with or without an equipment grounding conductor. For application of this section, the main power feeder shall be the feeder between the main disconnect and the lighting and appliance branch-circuit panelboard. The feeder conductors to a dwelling unit shall not be required to have an allowable ampacity rating greater than their service entrance conductors. The grounded conductor shall be permitted to be smaller than the ungrounded conductors, provided the requirements of 215.2, 220.61, and 230.42 are met.

Panel Statement: The panel agrees that the present wording is ambiguous. It is the panel?s intent that this allowance apply only to conductors carrying 100% of the dwelling unit?s diversified load.

Number Eligible to Vote: 11

Ballot Results: Affirmative: 11

 

[radiopet]

Ryan,

Thank you for chiming in Ryan.........it is always glad to know I am not totally insane in how I read it...and I stand behind my advice to the AHJ now....thank you all.

Guess the section is not as clear as it should be.......by the time VA adopts 2008....lol..it will be 2011....lol....so it should rage on for YEARS !

I screwed up my original post.....I actually agreed in the 310.15(b)(6) and how it applies......and told the guy the AHJ is ok.....but then after consulting with mike I was told I was wrong and it was clear cut....so then I posted this for clarrification......I think Ryan got all my posts on it...anyway I am glad to see my original advice was on the mark as I questioned it as well.....then started Questioning myself....and well......should always stick with the GUT !