Area controversy around sizing of GEC for ground rod

[Smart $]

...
It does not say where the gec is connected to A Rod, A Pipe, or A Plate electrode it says what it says....:grin: Where the GEC is connected to [strike]a[/strike] rod, pipe, or plate electrodes

...

That "s" doesn't do it. Granted it's part of a qualifying-condition phrase, but the condition further refined by the part which says "that portion of the conductor that is the sole connection to the grounding electrode". All words of this refinement phrase are singular.

 

[iwire]

You are using Charlie's rule but I read the rule differently then you do.

IMO that is because you are not reading it applying all of Charlies rule.

You are reading it looking for the result you want.

It does not say where the gec is connected to A Rod, A Pipe, or A Plate electrode it says what it says....:grin: Where the GEC is connected to a rod, pipe, or plate electrodes

I already covered this part, that 's' has to do with the fact the section is about 3 types of electrodes.

I think I will read it the way it looks to me as well as, I believe, most of the electrical community.

And for years many people in the electrical community thought 310.15(B)(6) could be applied to sub panels and when they were shown otherwise they said 'Oh that is not the intent' but the CMP said 'Yes, that is the intent'.

Perhaps the wording needs work

I do not think it does, I think it says what it means and means what it says.

I will propose to the CMP a change in wording and see what they say.

I really hope you do.

 

[Dennis Alwon]

I really hope you do.

Done -- sent in 2 minutes ago.

 

[roger]

Here are a couple of pertainent ROP's, since the forum does not support strike throughs the bold "electrode(s)" was the proposed change in the first.

5-173 Log #2481 NEC-P05
(250-66(A))
Final Action: Reject
Submitter: Paul Dobrowsky Holley, NY
Recommendation:
Revise as follows:
(A) Connections to Rod, Pipe, or Plate Electrodes. Where the grounding electrode conductor is connected to rod, pipe, or plate
electrodes as permitted in 250.52(A)(5) or 250.52(A)(6), that portion of the conductor that is the sole connection to the grounding
electrode(s) shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.
Substantiation:
Based on the information in Proposal 250-50 (2002 NEC) using a 6 AWG grounding electrode conductor is permitted for one or more of
these types of electrodes. This change will clearly point out that slash rated devices are permitted on solidly grounded systems only.
Panel Meeting Action: Reject
Panel Statement:
The conductor that joins grounding electrodes together is, by definition, a bonding jumper.
Number Eligible to Vote: 16
Ballot Results: Affirmative: 15 Negative: 1
Explanation of Negative:
DOBROWSKY: Although the panel statement is correct, the conductor sizing requirements for mroe than one "rod" type electrode is not adequately addressed and should be included.

5- 136 - (250-50): Reject
SUBMITTER: Noel Williams, Noel Williams Consulting
RECOMMENDATION: Add the following to the end of the
second paragraph:
"A grounding electrode conductor connecting to multiple made
electrodes as permitted in Section 250-52(c) or (d) shall be sized
according to Table 250-66. "
SUBSTANTIATION: According to the present rule, the
conductor to a single rod, pipe, or plate electrode need not be
larger than No. 6 copper (or No 4 aluminum). For a group of
made electrodes, the largest conductor required for any electrode
in the group is also No. 6 copper. Even where many such
electrodes are used as a grounding electrode system, the largest is
still No. 6. Therefore, where multiple made electrodes are used
to increase the overall contact area, the conductor is not required
to be increased under the present rule. This is inconsistent with
the reasoning behind Section 250-66(a). The rule as written is
not a problem when applied to concrete-encased electrodes or
ground rings, because even where multiple connections are made
they are all made to the same electrode(s).
PANEL ACTION: Reject.
PANEL STATEMENT: The panels intent is to permit the
specified size of grounding electrode conductors when connected
to single or multiple made electrodes.
NUMBER OF PANEL MEMBERS ELIGIBLE TO VOTE: 17
VOTE ON PANEL ACTION:
AFFIRMATIVE: 17

Roger

 

[Dennis Alwon]

So it appears the panel is saying that the intent is to not require larger than #6 to multiple rods. Yes?

 

[roger]

So it appears the panel is saying that the intent is to not require larger than #6 to multiple rods. Yes?

That's the way I read it.

Roger

 

[iwire]

So it appears the panel is saying that the intent is to not require larger than #6 to multiple rods. Yes?

Yes that is what it looks like to me.

I still say the words in the NEC do not support that.

Let me say I was on the same 'side' as you, Roger (and apparently the CMP although I clearly did not know that) until OregonSE posted this yesterday

Why 4#? Assuming CU. Sole connection, right?

250.66(A) Connections to Rod, Pipe, or Plate Electrodes.
Where the grounding electrode conductor is connected to
rod, pipe, or plate electrodes as permitted in 250.52(A)(5)
or (A)(7), that portion of the conductor that is the sole connection
to the grounding electrode shall not be required to be
larger than 6 AWG copper wire or 4 AWG aluminum wire.

Where there getting this is the first three words of 250.66a,connections to ROD,not RODS. So if you are running a single GEC from the MDP to your grounding electrode yes the # 6 applies but if you run it through the acorn clamp at the first rod and then to the second rod,# 4 would be required. So again either separate # 6 to each individual rods or a single # 4 for 2 RODS.

Once I read that it clicked to me to me that the way the section is written it only allows one electrode.

 

[roger]

Once I read that it clicked to me to me that the way the section is written it only allows one electrode.

But, (just food for thought) is one rod really an electrode by itself if it does not meet the 25 ohm requirement?

Roger

 

[iwire]

But, (just food for thought) is one rod really an electrode by itself if it does not meet the 25 ohm requirement?

Roger

Asked and answered :grin:

But yes, if we read 250.56 it specifically tells us it is. (IMO)

 

[Dennis Alwon]

Once I read that it clicked to me to me that the way the section is written it only allows one electrode.

Well well see in another 3 years what they have to say about my proposal. Unfortunately I proposed almost the same as the first proposal that Roger posted from the CMP, only I had a different reason and explanation.

 

[infinity]

Do we really know what this means?

...the sole connection
to the grounding electrode

 

[jxofaltrds]

Once I read that it clicked to me to me that the way the section is written it only allows one electrode.

Bob

Let's say that this is correct. A single electrode.

Now that we have a single electrode let's go to 250.56. We start with a 'single' electrode' that needs augmented. Are we adding a 'single' electrode or multiple electrodes? We are adding a 'single' electrode to augment it so back to 250.66 & 250.68 for the sizing and connection of the bonding jumper.

 

[infinity]

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?

 

[iwire]

Bob

Let's say that this is correct. A single electrode.

Now that we have a single electrode let's go to 250.56. We start with a 'single' electrode' that needs augmented. Are we adding a 'single' electrode or multiple electrodes? We are adding a 'single' electrode to augment it so back to 250.66 & 250.68 for the sizing and connection of the bonding jumper.

Mike please, at least read the posts. :roll:


When we read 250.56

250.56 Resistance of Rod, Pipe, and Plate Electrodes. A
single electrode consisting of a rod, pipe, or plate that does
not have a resistance to ground of 25 ohms or less shall be
augmented by one additional electrode of any of the types
specified by 250.52(A)(4) through (A)(8). Where multiple
rod, pipe, or plate electrodes are installed to meet the requirements
of this section, they shall not be less than 1.8 m
(6 ft) apart.

IMO that bolded section make it very clear that a single rod with a resistance above 25 ohms is still a 'single electrode'.

Furthermore in red it says 'shall be augmented by one additional electrode' you can't add an additional electrode if the first one is not an electrode.

 

[Dennis Alwon]

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?

What that doesn't make sense to you. :roll:

 

[iwire]

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?

IMO if the above service only requires a 6 AWG CU GEC per Table 250.66 there is nothing wrong with it at all.

However if this service requires a 4 AWG CU or larger GEC IMO it is in violation of the words in 250.66(A) because a single 6 AWG CU GEC is being used for more than one electrode.

 

[infinity]

What that doesn't make sense to you. :roll:

None. I'm still waiting for the definition of sole electrode.

 

[iwire]

I'm still waiting for the definition of sole electrode.

What?

Maybe I should just shut up now.

 

[jxofaltrds]

IMO if the above service only requires a 6 AWG CU GEC per Table 250.66 there is nothing wrong with it at all.

However if this service requires a 4 AWG CU or larger GEC IMO it is in violation of the words in 250.66(A) because a single 6 AWG CU GEC is being used for more than one electrode.

I did not know that a single GEC was allowed to supply multiple electrodes? Is that in 250.64?

As I read 250.68 the GEC must 'terminate' at an electrode.

 

[infinity]

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.