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#77901 - 07/20/01 04:55 PM 250-32
electure Offline


Member

Registered: 12/24/00
Posts: 4229
Loc: Fullerton, CA USA
A neighbor wants to put a 60A subpanel in his detached garage, about 30' from the house. He's doing it himself, has already run a UG 1" conduit with 3 #4, & a #8 EGC.
AHJ said he's required to install another grounding electrode @ the garage, but why?? I don't have a good answer for him.
His reasoning is that if the sub was on the fence, 30' further, it wouldn't be required. I can't argue with that.

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#77902 - 07/20/01 05:59 PM Re: 250-32
Tom Offline
Member

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
Electure,

Perhaps someone with access to the history of the NEC could give you the real "why" behind the code article.

The requirement is in 250-32 and in addition, 2 made electrodes will likely be required since this installation must still comply with 250-56.
_________________________
Few things are harder to put up with than the annoyance of a good example.

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#77903 - 07/20/01 06:43 PM Re: 250-32
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
why?
i ask that a lot too.

why can i run a 60A single circuit to my shed a mile away to weld with, and not do 2 G-rods?

why can i run a 4-wire 1/4 mile in the same building and not do G-rods?

why should i run a 3-wire 10' to an outbuilding and reground with 2 G-rods in close proximity to the serving buildings G-rods ( read into this, I double-dog dare ya!)

why does a disco rate more 'lighting protection" 30' from a mobiler home , that the home itself?

why is 'voltage gradient' not univerasl?

why?

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#77904 - 07/21/01 03:47 PM Re: 250-32
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
Quote:
Originally posted by sparky:
why?
i ask that a lot too.

why can i run a 60A single circuit to my shed a mile away to weld with, and not do 2 G-rods?

why can i run a 4-wire 1/4 mile in the same building and not do G-rods?

why should i run a 3-wire 10' to an outbuilding and reground with 2 G-rods in close proximity to the serving buildings G-rods ( read into this, I double-dog dare ya!)

why does a disco rate more 'lighting protection" 30' from a mobiler home , that the home itself?

why is 'voltage gradient' not univerasl?

why?



Reminds me of the philosophy student who got an A+ on the final exam.
The only question on the exam was "Why?"
His answer---"Why not?"

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#77905 - 07/21/01 05:34 PM Re: 250-32
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
it may as well be philsophical, for lack of rationale.....maybe someone would be kind enough to follow thru on Tom's suggestion.

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#77906 - 07/22/01 04:50 PM Re: 250-32
nesparky Offline
Member

Registered: 06/21/01
Posts: 650
Loc: omaha,ne
most inspectors call sheds, detached garages and light poles "seperate structures" Has nothing to do with actual electrical theory.
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ed

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#77907 - 07/22/01 10:31 PM Re: 250-32
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
nesparky,

It's interesting that you mentioned light poles. I've heard this before, is that true?

Do they require Gr rods at every pole location?

Bill

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#77908 - 07/23/01 05:15 AM Re: 250-32
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
The issue of a light pole being a structure has not be specifically addressed in the NEC. The was a code change in the 93 or 96 code in 225-32 to address this issue as far as a disconnecting means at a light pole. It seams that some inspectors, based on calling a light pole a structure, were requiring a disconnect at each pole (structure). 225-32 Exception #3 was added to say that a tower or pole used as a lighting standard can have its disconnect located elsewhere. Maybe we need the same type of exception in 250-32.
Don(resqcapt19)
_________________________
Don(resqcapt19)

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#77909 - 07/23/01 04:50 PM Re: 250-32
electure Offline


Member

Registered: 12/24/00
Posts: 4229
Loc: Fullerton, CA USA
Come to find out, the subject of my original Q has been absolutely dissected (in gargantuan proportions)in other BB's, without a final consensus in any of them.
It seems like this really needs to be addressed by the CMP, although I don't really know how they would/could reword it.
Any ideas?


[This message has been edited by electure (edited 07-23-2001).]

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#77910 - 07/24/01 01:14 AM Re: 250-32
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
elecuture,
i would say that looking at what our nieghbors do would be a good start.

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