Area controversy around sizing of GEC for ground rod

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radiopet said:
i think that clearly adding the additional electrode to the first ground rod does not make a multiple rod electrode but it does complete a grounding electrode system in this case. The problem is that I can see where it gets screwy in that clearly the sole connection to the first electrode (the first rod ) is not required to be larger than the 6 AWG. The problem starts when it says size the bonding jumper per 250.66 and the table gets used and so it becomes a situation where the bonding jumper from rod 1 to rod 2 is no longer a GEC . In this case I can see where someone can argue that the bonding jumper run to the second electrode cant use 250.66(A) and could lead to a larger bonding jumper.

However, I don't think this is the intent as I am quite sure lightning could careless but alas I am not engineer.
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Paul, it is not as "clearly" as you make it sound.

Regarding highlighted portion of your comment, 250.66(A) applies to the portion of a GEC that is the sole connection to the rpp-type electrode. You are viewing the connection to the first rod as the sole "GEC" connection, completely disregarding the bonding jumper connection to the first rod. There are "clearly" two grounding electrode system connections to this rod electrode. Elaborating on your viewpoint, explain to me how you would ever have an other than sole "GEC" connection to any electrode. The only way I can think of is to connect the same GEC to the same electrode twice (or more ;))... and it's neither required under any circumstance nor does anyone do it, and I certainly cannot fathom any reason for doing so.
 
radiopet said:
Roger,
For fun I sent for an informal opinion from the NFPA to see if they are on the same page. I know, it's informal and its not the CMP but hey....I always like to see. I agree in that #6 AWG should be all that is required but like iwire has stated and how it has been debated here......many opinions vary.
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Paul, let us know how they stand when you hear from them.

Thanks

Roger
 
Smart $ said:
...There are "clearly" two grounding electrode system connections to this rod electrode...
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That is my beef. I really don't see the single added augmentation rod to be a separate piece of a "system". To me, it is just another section of that one part and really is acting like part of one electrode.

As far as I'm concerned, and as far as how it behaves as an electrical component, the original rod combined with the augmentation rod is one electrode. Philosophically no different than adding sections and driving a real deep rod.

There is no electrical justification for having a larger wire between the original rod and the augmentation rod. If anything, you might could even justify a smaller wire.
 
mivey said:
That is my beef. I really don't see the single added augmentation rod to be a separate piece of a "system". To me, it is just another section of that one part and really is acting like part of one electrode.

As far as I'm concerned, and as far as how it behaves as an electrical component, the original rod combined with the augmentation rod is one electrode. Philosophically no different than adding sections and driving a real deep rod.

There is no electrical justification for having a larger wire between the original rod and the augmentation rod. If anything, you might could even justify a smaller wire.
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Correct. 250.53(B) calls them one system for 250.52(A)(5&7).

I now agree with the restrictions in 250.66. It took me a while to understand this.
 
LarryFine said:
In my opinion, the jumper is "the sole connection" to the second rod, and the #6 limit applies.

...
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Smart $ said:
I agree it is a sole connection... but the rule—250.66(A)—only applies to that portion of a GEC... not electrode bonding jumpers.
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jxofaltrds said:
Did you just flip on me? Are you saying that a sole connection can also have a bonding jumper?
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Remark stemmed from Larry's comment. The bonding jumper is the sole connection to the second rod... but there is no conditional phrase for "sole connection" made by a bonding jumper.

So no, I did not flip on you (but I may have thought about flipping you :D ... just kidding).
 
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Smart $ said:
Remark stemmed from Larry's comment. The bonding jumper is the sole connection to the second rod... but there is no conditional phrase for "sole connection" made by a bonding jumper.

So no, I did not flip on you (but I may have thought about flipping you :D ... just kidding).
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:) You and Bob and others were correct on the "sole connection".

Example: If the #6 was taken to the ground rod you could not 'bond' the waterline via the ground rod with a #6 or #4. You could bond the waterline with a #4 and a #4 supplying the rod from the service (assuming a 200AMP service). A #6 could be attached to the supplemental rod in the above example.
 
Smart $ said:
The bonding jumper is the sole connection to the second rod... but there is no conditional phrase for "sole connection" made by a bonding jumper.
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Maybe the augmenting electrodes should be called part of a sub-system instead of a system. This jumper is clearly different than other bonding jumpers in that everything eventually bottlenecks back to what would be #6 wire.

There is no electrical reason to have anything bigger downstream so maybe the panel felt it was obvious. Indeed, Roger's #44 seems to indicate that they thought it was obvious enough.
 
radiopet said:
Hmm...meet the exception to 250.53(A)(2) comes to mind. So, what exactly is an RPP-type electrode?:)
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I see you figured out what rpp is :)

As for the exception to 250.53(A)(2), I don't see any numbered subsection or condition to 250.53(A) let alone an exception thereto :confused:
 
mivey said:
Maybe the augmenting electrodes should be called part of a sub-system instead of a system. This jumper is clearly different than other bonding jumpers in that everything eventually bottlenecks back to what would be #6 wire.

There is no electrical reason to have anything bigger downstream so maybe the panel felt it was obvious. Indeed, Roger's #44 seems to indicate that they thought it was obvious enough.
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Bottlenecks back to what would otherwise be a #6... but because that would not be the sole connection to the electrode, its GEC has to be sized per Table 250.66... same as the bonding jumper.

Not obvious to me :roll:
 
Smart $ said:
Bottlenecks back to what would otherwise be a #6... but because that would not be the sole connection to the electrode, its GEC has to be sized per Table 250.66... same as the bonding jumper.
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It almost sounds like you think the GEC should be sized as a jumper, since it connects two rods, and the jumper should be sized as the GEC, since it connects only one rod.
 
radiopet said:
Hmm...meet the exception to 250.53(A)(2) comes to mind. So, what exactly is an RPP-type electrode?:)
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Smart $ said:
I see you figured out what rpp is :)

As for the exception to 250.53(A)(2), I don't see any numbered subsection or condition to 250.53(A) let alone an exception thereto :confused:
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Ohh! I see you are referring to the 2011 NEC...

...but I don't see you point relative to the issue (an other-than-sole connection of a GEC to an electrode). The only one(s) I can think of is bonding to the water pipe or structural steel electrode to establish an SDS GES (these are more common acronyms :))... but I was referring to an other-than-sole GEC connection from the same system. And the gist of the matter is that bonding jumper connections count when considering the "sole connection" condition.
 
LarryFine said:
It almost sounds like you think the GEC should be sized as a jumper, since it connects two rods, and the jumper should be sized as the GEC, since it connects only one rod.
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Its not what I think should be. I'm going by the Code wording.

250.66(A) permits a #6 GEC to an rpp-type electrode if that portion of the GEC is the sole connection to the rpp-type electrode. If a bonding jumper is connected from that rpp-type electrode to another electrode (doesn't matter what type), the bonding jumper connection constitutes a second connection to the rpp-type electrode. Therefore, 250.66(A) does not apply and the GEC to it must be sized per 250.66 general req't and thus Table 250.66.

The jumper must meet the requirements of 250.53(C) which says GESBJ's must be sized per 250.66. 250.66(A) only permits the sole connection portion of a GEC to be not larger than #6. Therefore, 250.66(A) does not apply to a GESBJ and must be sized per Table 250.66.
 
Original question

Original question

Smart $ said:
Its not what I think should be. I'm going by the Code wording.

250.66(A) permits a #6 GEC to an rpp-type electrode if that portion of the GEC is the sole connection to the rpp-type electrode. If a bonding jumper is connected from that rpp-type electrode to another electrode (doesn't matter what type), the bonding jumper connection constitutes a second connection to the rpp-type electrode. Therefore, 250.66(A) does not apply and the GEC to it must be sized per 250.66 general req't and thus Table 250.66.

The jumper must meet the requirements of 250.53(C) which says GESBJ's must be sized per 250.66. 250.66(A) only permits the sole connection portion of a GEC to be not larger than #6. Therefore, 250.66(A) does not apply to a GESBJ and must be sized per Table 250.66.
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So then, back to my original post that started this thread:

It was just a pedestal service, no building, foundation or water main involved. Just a pair of ground rods 5/8" X 8'. The contractor installed #4 cu to the rods and when the inspector showed, he failed him and demanded that the contractor install something in the neighborhood of 1/0 cu to the rods.

Smart$ are you agreeing with this inspector?
 
wbalsam1 said:
So then, back to my original post that started this thread:

It was just a pedestal service, no building, foundation or water main involved. Just a pair of ground rods 5/8" X 8'. The contractor installed #4 cu to the rods and when the inspector showed, he failed him and demanded that the contractor install something in the neighborhood of 1/0 cu to the rods.

Smart$ are you agreeing with this inspector?
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Unless speced before install, there is no way I am gonna run anything but #6 CU to a pair or rods.
 
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