Nec 2014 Article 250.64(D)(2)

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hhsting

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Does the attached sketch comply to NEC 2014 Article 250.64(D)(2)?
1dacfe262d9208275ab5ce483ae11c07.jpg


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Not in my opinion. The rod and the water main should be connected with a bonding jumper and only one GEC from each disco should go to either electrode. Also, to be a bit more nitpicky: the GECs should terminate on the neutral bars, not the equipment ground bars.
 
I hasten to add that I see multiple GECs to different electrodes all the time. But I can't recall seeing it on a service with multiple service disconnecting enclosures, only on single enclosure services.
 
jaggedben said:
Not in my opinion. The rod and the water main should be connected with a bonding jumper and only one GEC from each disco should go to either electrode. Also, to be a bit more nitpicky: the GECs should terminate on the neutral bars, not the equipment ground bars.
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A GEC can go to grounded conductor or equipment ground conductor feeding enclosure NEC 2014 Article 250.64(D)(2). Am I missing something? Also under ground metal pipe requires supplemental electrode so bonding jumer, one GEC needs to go to under ground metal pipe but within 5 feet of entrance. Am I missing something?

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hhsting said:
A GEC can go to grounded conductor or equipment ground conductor feeding enclosure NEC 2014 Article 250.64(D)(2). Am I missing something?
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In the 2014 NEC they revised this section to apply to both services and separate structures supplied by a feeder, 'as applicable'. So ...(D)(2)(1) applies to services with multiple disconnecting means, and ...(D)(2)(2) applies to a separate building with multiple disconnecting means for the feeder supplying it.

Also under ground metal pipe requires supplemental electrode so bonding jumer, one GEC needs to go to under ground metal pipe but within 5 feet of entrance. Am I missing something?
...
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You're generally right, but note that the section you originally asked about refers to 'a grounding electrode conductor' (singular). Also see 250.50, all electrodes should be bonded together to create one grounding electrode system. Best practice is to bond the electrodes together directly, not by running multiple GECs from each service disconnect, in my opinion. Code may or may not prohibit the multiple GECs for multiple disconnects, depending how you give weight to the wording of various sections.

One AHJ has been telling me for years that you have to bond the water pipe within 5ft, but the only reference to 5ft is in 250.68(C) which permits (doesn't require) the first 5ft to be used for bonding jumper connections to other electrodes.
 
jaggedben said:
In the 2014 NEC they revised this section to apply to both services and separate structures supplied by a feeder, 'as applicable'. So ...(D)(2)(1) applies to services with multiple disconnecting means, and ...(D)(2)(2) applies to a separate building with multiple disconnecting means for the feeder supplying it.



You're generally right, but note that the section you originally asked about refers to 'a grounding electrode conductor' (singular). Also see 250.50, all electrodes should be bonded together to create one grounding electrode system. Best practice is to bond the electrodes together directly, not by running multiple GECs from each service disconnect, in my opinion. Code may or may not prohibit the multiple GECs for multiple disconnects, depending how you give weight to the wording of various sections.

One AHJ has been telling me for years that you have to bond the water pipe within 5ft, but the only reference to 5ft is in 250.68(C) which permits (doesn't require) the first 5ft to be used for bonding jumper connections to other electrodes.
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I dont follow what you are saying. The question is if one provides single GEC from multiple service disconnects to under ground metal water pipe then NEC 2014 Article 250.53(D)(2) requires supplement electrode. The article 250.53(D)(2) exception to supplemental electrode requirement is 250.68(C)(1). So the GEC single from each service disco has to go to within 5 feet per 250.68(C)(1) and so does the bonding jumper to ground rod. What other configuration would there be that comply per NEC 2014 article 250?

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hhsting said:
I dont follow what you are saying. The question is if one provides single GEC from multiple service disconnects to under ground metal water pipe then NEC 2014 Article 250.53(D)(2) requires supplement electrode. The article 250.53(D)(2) exception to supplemental electrode requirement is 250.68(C)(1). So the GEC single from each service disco has to go to within 5 feet per 250.68(C)(1) and so does the bonding jumper to ground rod. What other configuration would there be that comply per NEC 2014 article 250?
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The article 250.53(D)(2) exception is 250.68(C)(1), Exception. That allows an industrial facility to bond the supplemental electrode to locations other than what's permitted in the rest of 250.53(D). 250.68(C)(1) is not a requirement; you can comply with 250.50 in other ways besides using the first 5ft of the water pipe, such as running bonding jumpers directly between electrodes.

I think there is a a conflict between what 250.53(D)(2) allows for the supplemental electrode connection and what 250.64(D)(2) describes for separate disconnect enclosures. The latter describes 'a grounding electrode conductor' (singular) connected to the 'grounding electrode system'. Your drawing in your original post has grounding electrode conductors (plural) running to otherwise unconnected electrodes, i.e. electrodes not bonded together in a system as required by 250.50. Running individual GECs to separate electrodes seems to be permitted for a service with a single disconnect enclosure, but not for one with multiple disconnect enclosures.

This is all pretty ticky-tack interpretation, and probably doesn't matter much, but hey, you asked so I gave an opinion. :D From a standpoint of personnel safety from shocks and such, I don't think any of this matters. From a standpoint of not exacerbating effects from lightning, I believe that 250.64(D)(1) or (3) would usually be a better choice than (2). But the code allows (2) as well.
 
250.64 (F) Installation of grounding electrode conductors to grounding electrodes

In any group of grounding electrodes bonded together you would only have one continuous grounding electrode conductor

If you take a (un-spliced) continuous grounding electrode conductor to a ground rod than bond a plate electrode to the rod grounding electrode you created a grounding electrode system

In the same building you can take another grounding electrode conductor individually to the building steel grounding electrode without any bond to another electrode

You can individually take grounding electrode conductors to as many building elements defined as grounding electrodes and as many man made electrodes as you choice to without any bonding conductors at all and be in compliance with 250.64

It is correct to say you only have one grounding electrode conductor in a bonded group

It is not correct to say that you can not install grounding electrode conductors individually to required electrodes on a building site

or you cannot individually ground a sytem to as many qualifying electrodes that you install
 
jaggedben said:
One AHJ has been telling me for years that you have to bond the water pipe within 5ft, but the only reference to 5ft is in 250.68(C) which permits (doesn't require) the first 5ft to be used for bonding jumper connections to other electrodes.
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you are correct you do not have to use the permitted section for bonding metal pipe within the first five ft for the metal underground water pipe electrode (10 ft or more in direct contact with earth 250.52 (A) (1) )

You could choice instead be there before the electrode is buried or dig down to frost depth here being 36 in min and connect directly to the metal pipe electrode

I do not think your reading is wrong, it is permitted not required to use the 5 ft bonding point, I also do not think your authority was wrong either just not stated correctly, your authority most likely knew you would use the permitted bonding point instead of digging to the 10 ft pipe electrode
 
jaggedben said:
Also, to be a bit more nitpicky: the GECs should terminate on the neutral bars, not the equipment ground bars.
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Don't forget the allowance in this section also take note that the (green) screw type main bonding jumper is not mentioned in 250.24 (D)

250.24 (D)
Main Bonding Jumper as Wire or Busbar. Where the main bonding jumper specified in 250.28 is a wire or busbar and is installed from the grounded conductor terminal bar or bus to the equipment grounding terminal bar or bus in the service equipment, the grounding electrode conductor shall be permitted to be connected to the equipment grounding terminal, bar, or bus to which the main bonding jumper is connected.

jaggedben said:
. Best practice is to bond the electrodes together directly, not by running multiple GECs from each service disconnect, in my opinion.
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I agree with this line of reasoning, though you do not need my confirmation since the threads you post in here indicate you are pretty knowledgeable
 
hhsting said:
Does the attached sketch comply to NEC 2014 Article 250.64(D)(2)?
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Note the NEC requires a direct connection of the grounding electrode conductor to the systems
grounded conductor

or bus that the grounded service conductor is connected to

or to a bus/terminal a main boding jumper from the grounded conductor is connected to.

“ General. The grounding electrode conductor connection shall be made at any accessible point from the load end of the service drop or service lateral to and including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means.”

It is my opinion that the required bonding of the grounding electrodes (system) in 250.50 is met when the grounding electrode conductor or conductors, connect to the allowable neutral bus or main bonding jumped terminal or bus that the grounded conductor is bonded to.

By bonding as many grounding electrode conductors that are installed to the allowed bonded points as stated in 250.64 (F)
 
david said:
Now don’t be too hard on me after all I did compliment your knowledge in this thread
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lol
Thanks for pointing out 250.64(F), which I lost track of. I don't think I disagree with anything you said. I still think that for the special case of multiple service disconnects the code language seems to specify something slightly more restrictive than for the general case. That's my opinion, anyway. :cool:
 
Looks like answer is confusing. One NEC article says yes and another one says no. Nec 250.64(F) says you can however there is discrapancy Nec 250.64(D)(2) clearly states single GEC. So which one is it?
 
hhsting said:
Looks like answer is confusing. One NEC article says yes and another one says no. Nec 250.64(F) says you can however there is discrapancy Nec 250.64(D)(2) clearly states single GEC. So which one is it?
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250.64 (D) (2)
Individual grounding electrode conductors

connected to each of the grouped service disconnects

I see 250.64 (F) applicable to the common grounding electrode conductor in 250.64 (D) (1) as well as to the individual grouped service disconnects in 250.64 (D ) (2)
 
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