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#77901 07/20/01 07:55 PM
Joined: Dec 2000
Posts: 4,294
Member
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 08:59 PM
Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
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.
#77903 07/20/01 09:43 PM
Joined: Oct 2000
Posts: 5,392
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Member
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?

#77904 07/21/01 06:47 PM
Joined: Mar 2001
Posts: 2,056
R
Member
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?"

#77905 07/21/01 08:34 PM
Joined: Oct 2000
Posts: 5,392
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Member
it may as well be philsophical, for lack of rationale.....maybe someone would be kind enough to follow thru on Tom's suggestion.

#77906 07/22/01 07:50 PM
Joined: Jun 2001
Posts: 642
N
Member
most inspectors call sheds, detached garages and light poles "seperate structures" Has nothing to do with actual electrical theory.


ed
#77907 07/23/01 01:31 AM
Joined: Oct 2000
Posts: 4,116
Likes: 4
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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


Bill
#77908 07/23/01 08:15 AM
Joined: Nov 2000
Posts: 2,148
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Member
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)
#77909 07/23/01 07:50 PM
Joined: Dec 2000
Posts: 4,294
Member
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).]

#77910 07/24/01 04:14 AM
Joined: Oct 2000
Posts: 5,392
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elecuture,
i would say that looking at what our nieghbors do would be a good start.

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