point of connection [RE-wrenches]

[Joel Davidson]

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Hello Dick,

Thank you very much for summarizing the point of connection discussion. I 
couldn't help but smile at your introductory paragraph. Many wrenches, 
including me, buy a handbook every few years. The color pictures sort of 
remind me of an illustrated "How Things Work."

You forgot to include the ten inspectors that are also interpreting the Code 
in ten different ways. The image that comes to my mind is a medieval town 
with craftsmen building the city hall. The master craftsman tells his 
apprentices WHAT to do and HOW to do it. That evening at the Guild Hall over 
drinks, the day's work is discussed and on Sunday, the priest discusses WHY 
things are done a certain way.

There will always be craftsmen who try new ways to do things even in the 
face of punishment for heresy. And there will always be priests who use 
their power for personal gain. And there will be workers as described this 
supposedly true story about W.C. Fields on his deathbed. All is friends were 
in the parlor on death watch. One friends stuck his head in W.C.'s bedroom 
door to see how he was doing. W.C. lay there with a bible on his lap. His 
friend was amazed that the irreligious W.C. had finally found religion and 
asked, "What do you hope to find?" "Loopholes."

Joel Davidson

----- Original Message ----- 
From: "Dick Ratico" <Richard.L.Ratico at VALLEY.NET>
To: <RE-wrenches at topica.com>
Sent: Monday, May 05, 2008 8:13 PM
Subject: RE: point of connection [RE-wrenches]


>
> Ryan, Bill, Wrenches,
>
> Every couple of code cycles I spring for the hardbound code handbook. It's 
> two
> inches thick, costs $115, and has....PICTURES :-)  .....and lots of 
> additional
> text in an all too often vain attempt to try to explain the actual, 
> official
> text. You know you're in trouble when you need a book to explain a book 
> about
> electrical safety. It is not user friendly. Its dry as dirt. The index 
> sucks.
> Ask ten electricians or PV techs how they'll interpret the code, 
> particularly as
> regards grounding, and you're lucky to reach a concensus. Most of you who 
> post
> on this list have much more PV experience than I do. I have mostly lurked 
> here,
> for years. I try to read it twice a day. You're my most valuable resource. 
> Thank
> you all!
>
> Article 100 defines Service, Service Cable, Service Drop, Service Entrance
> Conductors, Service Equipment, Service Lateral and Service Point.
>
> The basic idea is, in general, a structure should be connected to the 
> serving
> utility at only one location, using one set of conductors, using a maximum 
> of
> six switches. The code is all about safety. In case of an emergency 
> situation
> you want to be able to disconnect the entire structure from the serving 
> utility
> as quickly and efficiently as possible. There needs to be a pretty good 
> reason
> for the utility to provide another, entirely separate SERVICE DROP to the
> building, usually in a different location on the building, to provide for 
> an
> additional, separate SERVICE.
>
> Ryan Wrote:
> I'm not sure I see the reason a UI inverter can't be viewed as a parallel 
> power
> production system and be eligible for the allowance under 230.2(A)(6). The
> definition of a utility
> interactive inverter is "an inverter intended for use in parallel with an
> electric utility to supply common loads that may deliver power to the 
> utility."
> This is the exact reference I have
> used to connect a PV system on the supply side of a MDP that had 6 service
> disconnects in it already.
>
> Reply:
> If you've connected the PV system to the supply side of the MDP, you're 
> still
> connected to the same utility SERVICE DROP the MDP is connected to. It's 
> not a
> separate SERVICE unless its supplied by an entirely different set of 
> conductors
> from the utility's system. Picture, for instance, two separate overhead 
> cables
> from the utility's pole mounted transformer connected to two distinct sets 
> of
> SERVICE EQUIPMENT (each with its own meter) on the building.
>
> It appears you've added a seventh switch to the building's single SERVICE. 
> I
> think most inspectors would consider this a violation. However, it would 
> most
> likely have been quite costly to reconfigure the existing SERVICE 
> EQUIPMENT to
> have six or less switches including the one for the PV. Six, seven, what's 
> one
> more? An inspector might let it fly. It's their call, but six has been in 
> the
> code a long time.
>
> Ryan wrote:
> 705.12 actually uses the language "interconnected electric power source" 
> not
> "parallel power production system" (this is probably splitting hairs 
> though). I
> don't see how 705.12(B) and (C) preclude a PV system to be included in the
> 230.2(A)(6) allowance. Am I understanding you correctly?
>
> Reply:
> Busted! I agree about the hair splitting though, because I can't find 
> "Parallel
> power production system" anywhere in the code, other than 203.2(A)(5).
>
> The six Special Conditions of 230.2(A) which do permit a separate SERVICE, 
> seem
> to address the issues of safety, law, and power reliability / redundancy. 
> As
> much as we all like PV, it's hard to see non-battery backed up PV included 
> in
> this list. It still gets cloudy. It still gets dark every night. If the 
> grid
> goes down, so does the PV. Article705.12(C) does allow a separate SERVICE 
> for
> PV,  ......as long as it's over 100kW or 1000 volts.
>
> Ryan wrote:
> I am also confused by "The much more common situation permitted by 
> 705.12(A) is
> ONE service." Wouldn't the new PV connection constitute a new service
> disconnect?
>
> Reply:
> The new PV connection definitely constitutes a new, additional switch
> (disconnect) (#7) in the existing, single SERVICE. It, in no way, can be
> considered a separate SERVICE, because it shares the existing utility 
> SERVICE
> DROP with the MDP, rather than being SERVED with it's own, separate 
> utility
> SERVICE DROP.
>
> Hope this helps,
> Dick
>
>
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>
> 


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