# Art. 250.30(A)(6) 2008/2011



## Rockyd (Apr 22, 2007)

What no players?

I know the things isn't perfect...that's why aI brought it here, get some input...:thumbsup:


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## HARRY304E (Sep 15, 2010)

Rockyd said:


> What no players?
> 
> I know the things isn't perfect...that's why aI brought it here, get some input...:thumbsup:


*Art. 250.30(A)(6) 2008/2011* 
Working on NEC changes 2008 vs. 2011. Namely, putting together some test questions for Article 250. So will probably ask a few too many questions between here and September… (Hearing this is a likely time when we will be adapting the 2011 NEC). So will start off easy, and get rougher as it goes.
Looks like there was a shift in the section numbering – 

*2008 *250.30(A) (*4*) is now *2008* 250.30(A) (*6*) 
Conceptually the same from what my research shows me.
Looks okay to me – 

Sizing the *Common Grounding Electrode Conductor*

Still can’t be smaller than 3/0 Cu or 250 Kcmil Al.

Still based on 250.66 largest ungrounded conductor of the separately derived system it serves

*A connector has to be listed as grounding and bonding equipment.*

Bus bar is not *smaller* than ¼” x 2” with Aluminum rider 250.64(a)

The exothermic welding process is still acceptable (use the new “smokeless” electric fired charges, don’t need no fire alarm drill in a high rise! :no

Concept wise it looks good…now let the critics tear it up!

Need to know if I'm missing much on this? 

Does this help...:laughing:


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## HARRY304E (Sep 15, 2010)

250.30(A)(6) is mostly new in the 2011 NEC..

*
(6) Grounding Electrode Conductor, Multiple Separately
Derived Systems.​*​​​​A common grounding electrode
conductor for multiple separately derived systems shall be
permitted. If installed, the common grounding electrode
conductor shall be used to connect the grounded conductor
of the separately derived systems to the grounding electrode
as specified in 250.30(A)(4). A grounding electrode
conductor tap shall then be installed from each separately
derived system to the common grounding electrode conductor.
Each tap conductor shall connect the grounded conductor
of the separately derived system to the common
grounding electrode conductor. This connection shall be
made at the same point on the separately derived system
where the system bonding jumper is connected.​
_Exception No. 1: If the system bonding jumper specified in
250.30(A)(1) is a wire or busbar, it shall be permitted to
connect the grounding electrode conductor tap to the
equipment grounding terminal, bar, or bus, provided the
equipment grounding terminal, bar, or bus is of suffıcient
size for the separately derived system.
Exception No. 2: A grounding electrode conductor shall not​be required for a system that supplies a Class 1, Class 2, or
Class 3 circuit and is derived from a transformer rated not
more than 1000 volt-amperes, provided the system grounded
conductor is bonded to the transformer frame or enclosure by
a jumper sized in accordance with 250.30(A)(1), Exception
No. 3, and the transformer frame or enclosure is grounded by​one of the means specified in 250.134.
_


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## nitro71 (Sep 17, 2009)

I'm just tired and a bit buzzed. Was working a 100' up on grain elevator leg today. Little bit of pucker factor involved.


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## Rockyd (Apr 22, 2007)

nitro71 said:


> I'm just tired and a bit buzzed. Was working a 100' up on grain elevator leg today. Little bit of pucker factor involved.


 
Never done much ag...but a 100' of free air under the butt always makes for a long day. How many "penalty climbs?:laughing: I hate those "extra trips" for ANY reason!!:thumbsup::no:


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## nitro71 (Sep 17, 2009)

Luckily, the first 80 or so was in side the elevator. Then the leg was 30' up or so. So 30's free air on top of the tower. Leg seemed shaky. I'll go back for more.. Had a manual man lift(rope driven) so not to bad on trips.


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## raider1 (Jan 22, 2007)

Rockyd said:


> Working on NEC changes 2008 vs. 2011. Namely, putting together some test questions for Article 250. So will probably ask a few too many questions between here and September… (Hearing this is a likely time when we will be adapting the 2011 NEC). So will start off easy, and get rougher as it goes.
> Looks like there was a shift in the section numbering –


Yes, the major change to 250.30 is a reorganization and renumbering for clarity.


*



2008

Click to expand...

*


> 250.30(A) (*4*) is now *2008* 250.30(A) (*6*)
> Conceptually the same from what my research shows me.
> Looks okay to me –


Correct, the concept of a common grounding electrode for multiple separately derived systems is basically the same.




> Sizing the *Common Grounding Electrode Conductor*
> 
> Still can’t be smaller than 3/0 Cu or 250 Kcmil Al.
> 
> Still based on 250.66 largest ungrounded conductor of the separately derived system it serves


Correct, but they also added that the metal frame of a building that complies with 250.52(A)(2) also qualifies as a common grounding electrode.


*



A connector has to be listed as grounding and bonding equipment.

Click to expand...

*Correct, 250.30(A)(6)(c)(1) changed from just a listed connector to a connector listed as grounding and bonding equipment.





> Bus bar is not *smaller* than ¼” x 2” with Aluminum rider 250.64(a)
> 
> The exothermic welding process is still acceptable (use the new “smokeless” electric fired charges, don’t need no fire alarm drill in a high rise! :no
> 
> ...


Nope, for the common grounding electrode requirements for separately derived systems it seems you got it.:thumbsup:

Chris


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## Rockyd (Apr 22, 2007)

Thanks Chris, that is exactly what I needed!:thumbsup:


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## Rockyd (Apr 22, 2007)

HARRY304E said:


> 250.30(A)(6) is mostly new in the 2011 NEC..
> 
> 
> *(6) Grounding Electrode Conductor, Multiple Separately*​
> ...




Nice try Harry...but I'm having to go through Art. 250 and anything new in *thought* as well as verbiage, I'm going to have to approach, be prepared to explain, and justify. So doing the all ahead, dead slow crawl through NEC, NECH, and a few Mike Holt books to make sure that my information is correct. 

I don't think there is that much new out there, some new direction with a couple of thought patterns, clarity has been added, verbiage cleaned up. 

I was a critic over part of what was put out in regard to style and verbiage, without justification in grounding and bonding last code cycle on information in testing for CEU's. So instead of being just a critic, offered to help fix what I perceived to be problems - so I have my work cut out for me. 

My verbiage doesn't need to be prefect, but the information I submit, needs to be best available. Tossing items that have potential for error, out here in the forum, is always a good critique zone. If it's not correct, I'm sure that are plenty of sharp people out there that will let me know!

Made it throught the 250.24 re-work, now on 250.30, Make it through 30 looks like it will be pretty easy after that. 250..66 and 250.122 look pretty much the same:thumbup:

Have to watch my tongue next time I have an opportunity to be ugly....:laughing: 


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