Area controversy around sizing of GEC for ground rod

[jxofaltrds]

Will it's just my opinion but I don't see how decades of installations are suddenly incorrect based on a new interpretation of old code language. Certainly this section has been read millions of times yet no one, including Mike Holt has come to some of the conclusions made in this thread. IMO that would indicate that there is something incorrect in that new interpretation.

I would center on the words sole connection and how they relate to the requirement. IMO they mean that when using plate, rod or pipe eletrodes the GEC need not be larger than #6 Cu. If you were to continue on to another electrode, say a water pipe then you would not have a sole connection to the rod, pipe or plate electrode since the GEC continues to a different electrode.

So what about the "sole connection(s)" in (B) & C)?

 

[jxofaltrds]

Do we really know what this means?

Would this be a sole connection for the GEC and a bonding jumper?
http://galvanelectrical.com/nr2008-2.asp

Is an acorn listed for feed through? I mean a GEC turning into a bonding jumper.

 

[wbalsam1]

My take on it

My take on it

250.64(F) states that "The GEC shall be sized for the largest GEC required among all the electrodes connected to it". So, no matter how many 5/8 X 8' grounding electrodes you have connected together, either by bonding jumpers or individually, the GEC does not have to be larger than #6 cu.

250.66(A), like so much of the rest of the code, uses plurals interrelated where the functioning of one part is controlled by the functioning of another part. For example, the first word in 250.66(A) is a plural: Connections. The nouns "rod", "pipe" and "plate" are intended to share the plural "s" from the last noun in the sentence "electrode(s)".

 

[Dennis Alwon]

Is an acorn listed for feed through? I mean a GEC turning into a bonding jumper.

You are kidding, I hope. For that matter then every acorn could not extend beyond the end of the clamp. Doesn't a CEE turn into a GEC.

The part that extends to the second rod is a bonding jumper. So the code allows a 6 awg to the rod, but being a bonding jumper I would need a 4 awg to the second rod from the first. Yes I am being facetious.

I totally agree with Trevor, Rob & Infinity D ) , and Rogers post of the response CMP appears to agree with that interpretation. You can play with the words all you want and Oregon is obviously doing what they want but I feel it is an incorrect interpretation.

 

[OregonSE]

So what's the argument here? Assume this is a 200 amp service as per the OP. This is compliant because the two rods are connected by a bonding jumper, but if the rod on the left had only one clamp with the GEC run through it then it isn't compliant?

I see the copy right on that picture is 2005. The bonding jumper does not meet 2008 code.
This issue was brought up at a 2008 Oregon code change meeting. In Oregon when installing a grounding electrode using ground rods, see 250.56 then 250.64(F)1 & 2 .

 

[jxofaltrds]

I see the copy right on that picture is 2005. The bonding jumper does not meet 2008 code.
This issue was brought up at a 2008 Oregon code change meeting. In Oregon when installing a grounding electrode using ground rods, see 250.56 then 250.64(F)1 & 2 .

It does meet the 2008. 250.64(F) 'size' only applies if you use 'one' GEC to connect to different types of electrodes. It does not apply to bonding jumpers.

Example hitting the ground rod on my way to the waterline.

If I am not clear someone else jump in.

EDIT 250.64(F)(1) takes you to 250.53(C) which takes you to 250.66.

 

[roger]

If I am not clear someone else jump in.

Mike, you are very clear and I agree with you and so does the CMP.

Roger

 

[jxofaltrds]

Mike, you are very clear and I agree with you and so does the CMP.

Roger

Thanxs. My written skills are not as good as my verbal skills.

 

[Smart $]

It does meet the 2008. 250.64(F) 'size' only applies if you use 'one' GEC to connect to different types of electrodes. It does not apply to bonding jumpers.

Example hitting the ground rod on my way to the waterline.

If I am not clear someone else jump in.

EDIT 250.64(F)(1) takes you to 250.53(C) which takes you to 250.66.

I believe your conclusion is inline with Code intent, but your interpretation of the wording is slightly off...

First, 250.64(F) applies to GEC(s) and bonding jumpers...

(F) Installation to Electrode(s). Grounding electrode con-
ductor(s) and bonding jumpers interconnecting grounding
electrodes...

In the MH illustration, the bonding jumper between rods is sized per 250.66(A). That is in error. Yes, it is a bonding jumper... but 250.66(A) does not say anything about the sizing of bonding jumpers. It specifically states GEC in the basic qualifying-condition phrase, then further refines that to only the portion of a GEC that is the sole connection to the grounding electrode. As such, we cannot size a bonding jumper between rpp-type electrodes per 250.66(A).

Regarding 250.64(F) general statement...

"The grounding electrode conductor shall be sized for
the largest grounding electrode conductor required among
all the electrodes connected to it.

Again there is nothing in this statement regarding bonding jumpers.

The sizing requirement for bonding jumpers is 250.53(C), and AFAICT there is no section which counters this requirement by specifically using "bonding jumper" in its qualifying-condition phrase.

 

[jxofaltrds]

I believe your conclusion is inline with Code intent, but your interpretation of the wording is slightly off...

First, 250.64(F) applies to GEC(s) and bonding jumpers...

​

In the MH illustration, the bonding jumper between rods is sized per 250.66(A). That is in error. Yes, it is a bonding jumper... but 250.66(A) does not say anything about the sizing of bonding jumpers. It specifically states GEC in the basic qualifying-condition phrase, then further refines that to only the portion of a GEC that is the sole connection to the grounding electrode. As such, we cannot size a bonding jumper between rpp-type electrodes per 250.66(A).

Regarding 250.64(F) general statement...

​

Again there is nothing in this statement regarding bonding jumpers.

The sizing requirement for bonding jumpers is 250.53(C), and AFAICT there is no section which counters this requirement by specifically using "bonding jumper" in its qualifying-condition phrase.

I think that you just agreed with me.

 

[Smart $]

Forgot to add...

The only way I see to have the rods in the illustration connected with only #6, disregarding intent and going only by wording, would be to branch the GEC. That would require a splice somewhere in the GEC run such that a single conductor (GEC) runs to each rod.

 

[Smart $]

I see the copy right on that picture is 2005. The bonding jumper does not meet 2008 code.
This issue was brought up at a 2008 Oregon code change meeting. In Oregon when installing a grounding electrode using ground rods, see 250.56 then 250.64(F)1 & 2 .

It does meet the 2008. 250.64(F) 'size' only applies if you use 'one' GEC to connect to different types of electrodes. It does not apply to bonding jumpers.

Example hitting the ground rod on my way to the waterline.

If I am not clear someone else jump in.

EDIT 250.64(F)(1) takes you to 250.53(C) which takes you to 250.66.

I think that you just agreed with me.

I think not. You said the illustration meets 2008 Code. By literal interpretation, disregarding intent, the illustration does not meet 2008 Code. The bonding jumper in the illustration is sized per 250.66(A), which no part of regards the sizing of an electrode bonding jumper.

 

[Dennis Alwon]

​

The bonding jumper in the illustration is sized per 250.66(A), which no part of regards the sizing of an electrode bonding jumper.

So if I jumped the 2 rods with the appropriate size GEC and left the #6 to the first rod I would be compliant?

 

[Smart $]

So if I jumped the 2 rods with the appropriate size GEC and left the #6 to the first rod I would be compliant?

IMO, and I emphasize by literal interpretation only, you would not. 250.66(A) "allows" #6 GEC to a rod... but only if the sole connection. Adding the bonding jumper to the second rod makes the GEC connection to the first rod NOT the sole connection. As such, you would have to run a sized-per-table GEC and bonding jumper.

 

[wbalsam1]

​

I think not. You said the illustration meets 2008 Code. By literal interpretation, disregarding intent, the illustration does not meet 2008 Code. The bonding jumper in the illustration is sized per 250.66(A), which no part of regards the sizing of an electrode bonding jumper.

I agree that the citation of 250.66(A) was improperly used in the Mike Holt slide for the 2005 code. In actuality, the proper citation would have been 250.53(E) when discussing the proper size bonding jumper between rods. (Same for 2008)

 

[iwire]

IMO, and I emphasize by literal interpretation only, you would not. 250.66(A) "allows" #6 GEC to a rod... but only if the sole connection. Adding the bonding jumper to the second rod makes the GEC connection to the first rod NOT the sole connection. As such, you would have to run a sized-per-table GEC and bonding jumper.

Which is all I have been trying to say all along and I thank you for jumping in.

I did entirely miss the bonding jumper angle of this and agree that is a problem in the image Rob posted.

 

[jxofaltrds]

​

I think not. You said the illustration meets 2008 Code. By literal interpretation, disregarding intent, the illustration does not meet 2008 Code. The bonding jumper in the illustration is sized per 250.66(A), which no part of regards the sizing of an electrode bonding jumper.

The illustration is correct for the 2008.

Where is "electrode bonding jumper"?

Explain to me how Exhibit 250.31 works since the waterline has no 'sole connection'?

I wish they had used 350 for the service conductors.

 

[jxofaltrds]

I agree that the citation of 250.66(A) was improperly used in the Mike Holt slide for the 2005 code. In actuality, the proper citation would have been 250.53(E) when discussing the proper size bonding jumper between rods. (Same for 2008)

Using 'others' logic 250.53(E) does not apply. Note the word "sole".

Edit. Also it is not a supplemental electrode.

 

[wbalsam1]

When using bonding jumpers between various electrodes the use of the word "sole" connection is pretty well visually explained in this slide. I could extend a #6 cu bonding jumper from ground rod #5 to another ground rod say, #7.

 

[wbalsam1]

Using 'others' logic 250.53(E) does not apply. Note the word "sole".

Edit. Also it is not a supplemental electrode.

If I run a #4 cu from the service equipment panel to the metallic water main and along the route of this grounding electrode conductor I provide an #6 cu irreversibly connected to this #4 GEC and along the way route this #6 to a ground rod, then the connection I make to the rod is the sole connection from this conductor. If I add another supplemental rod to this rod by means of a bonding jumper, I have made no additional connection to the GEC, I've connected to the electrode itself.