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#5232 - 11/09/01 07:10 PM Multiple services & Neutral bonding  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
A couple of topics here got me to thinking some more about multiple services to a building.

Suppose you have a commercial building fed with 277/480V Wye. O.K, so perhaps in most cases there would be a customer-owned xfmr to get local 120/208 service, but what if the PoCo provides a separate 120/208V Wye (or a 1-ph 3-w 120/240V supply).

If the NEC requires neutral-ground bonding at each main panel, how does the PoCo feel about having the neutrals of two different services effectively connected together in this way?


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#5233 - 11/09/01 09:01 PM Re: Multiple services & Neutral bonding  
ElectricAL  Offline
Member
Joined: Oct 2001
Posts: 597
Minneapolis, MN USA
In my experience, the power company enforces the grounding of the neutral at the building as part of their pre-energization tests, even when there is no other AHJ. In the un-inspected areas I have experienced, the PoCo lineman will make sure the neutral is bonded to ground before he runs the service lateral. . .anything else may well be ignored, but not that. I take that as evidence that the PoCo is all for the neutral ground bond even when it cross neutrals different systems.

Al


Al Hildenbrand

#5234 - 11/09/01 10:18 PM Re: Multiple services & Neutral bonding  
sparky  Offline
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Joined: Oct 2000
Posts: 5,303
There really cannot be any true N isolation with the N&G practice used here, be it under one roof, or having a common municipal bond.


#5235 - 11/10/01 07:20 AM Re: Multiple services & Neutral bonding  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Yeah, that's pretty much what I was thinking from the recent posts on this.

I can see more of this discussion arising in the U.K. with the increasing use of PME (i.e. bonded N-G).


#5236 - 11/10/01 07:50 AM Re: Multiple services & Neutral bonding  
sparky  Offline
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Joined: Oct 2000
Posts: 5,303
There has been, ROP's as i understand, as to a N-G separation back to the serving X-former. The NEC has dictated 'codes' for many other trades, but that seems to stop at the utilities, who seem impenetrable.


#5237 - 11/10/01 01:05 PM Re: Multiple services & Neutral bonding  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Something like the U.K. system in my diagram #1, you mean? I have to confess that I like that system a lot, although I wouldn't be adverse to installing a ground rod at each house as well, just to be certain.

What's ROP by the way?


#5238 - 11/10/01 05:52 PM Re: Multiple services & Neutral bonding  
electure  Offline


Member
Joined: Dec 2000
Posts: 4,259
Fullerton, CA USA
Way off the subject, but we have a "Regional Occupational Program"(ROP) in the high schools here, which teaches mainly agricultural occupations.
Here in North Orange County, it is abbreviated as NO CROP [Linked Image]


#5239 - 11/11/01 09:20 AM Re: Multiple services & Neutral bonding  
sparky  Offline
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Joined: Oct 2000
Posts: 5,303
Scott, soundslike a federal program [Linked Image]

Paul; http://www.nfpa.org/Codes/National_Electrical_CodeR__NEC/Proposals/necpdf/A250.PDF
ROP= Report on Proposal, anyone can write and submit one, but it usually needs to be of indisputable quailty to amount to an NEC change.

there are ROC's = Report on comments, where there are some points of views that are , at least in my opinion, real rippers. One individual's letter on the recent change of 'fixture' to 'lumiaire' eluded to plumbers mistakenly mounting toilets on kitchen cielings , absolute 5-star ripper! [Linked Image]


#5240 - 11/12/01 04:39 PM Re: Multiple services & Neutral bonding  
Scott35  Offline

Broom Pusher and
Member
Joined: Oct 2000
Posts: 2,707
Anaheim, CA. USA
Scott [electure],

Haven't heard about NOCROP for years!!! I learned Diesel Mechanics in 1982-3 at Loara High School in a NOCROP program.
Give me a call sometime [Linked Image]

As to this thread;

I have seen a few PoCo supplied systems / services as described. Seems to me that the whole thing would be as any other type of "Dual Services" or even SDS [Separately Derived System] would be - as far as the Grounding / Grounding Electrode System is concerned.

Just my thoughts.

Scott SET.


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!


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