GEC

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MannyBurgos

Senior Member
Location
Waukegan, IL
Hello all. I am sure this has been bitten in the butt somewhere in here many times but here is my question: When you have (2) GEC's such as (1) ground rod and (1) water meter pipe in direct contact with earth for 10+ feet, which is considered your "primary" GEC?

In this case, where does bonding come into place besides the bonding bushing?
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
I would say the water pipe is your main and the ground rod is supplementary. Instead of ground rod you can use a pipe, plate, grounding ring...
 

John120/240

Senior Member
Location
Olathe, Kansas
Hello all. I am sure this has been bitten in the butt somewhere in here many times but here is my question: When you have (2) GEC's such as (1) ground rod and (1) water meter pipe in direct contact with earth for 10+ feet, which is considered your "primary" GEC?

In this case, where does bonding come into place besides the bonding bushing?

Every thing after the first OCPD is bonding. One example some localities require bonding of the Hot & Cold metallic water pipes at the water heater.
 

MannyBurgos

Senior Member
Location
Waukegan, IL
Ok, so you guys helped me put a better question together: which is considered the GEC and which is the bonding jumper (if applicable); the conductor going from meter neutral to ground rod or the conductor going from main disconnect neutral bar to water meter?
 

Smart $

Esteemed Member
Location
Ohio
Ok, so you guys helped me put a better question together: which is considered the GEC and which is the bonding jumper (if applicable); the conductor going from meter neutral to ground rod or the conductor going from main disconnect neutral bar to water meter?
In this case, you actually have two GEC's and both are "primary".

That said, Code makes no "primary" electrode distinction (except one is implied by a supplementary electrode requirement), but in the case where multiple electrodes are tied to one GEC, whether directly or by bonding jumper, and if any one of those were to be considered "primary", I'd say it is the one which has no maximum GEC size exemption under 250.66.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Hello all. I am sure this has been bitten in the butt somewhere in here many times but here is my question: When you have (2) GEC's such as (1) ground rod and (1) water meter pipe in direct contact with earth for 10+ feet, which is considered your "primary" GEC?

In this case, where does bonding come into place besides the bonding bushing?


What are you trying to do?
 

kwired

Electron manager
Location
NE Nebraska
In this case, you actually have two GEC's and both are "primary".

That said, Code makes no "primary" electrode distinction (except one is implied by a supplementary electrode requirement), but in the case where multiple electrodes are tied to one GEC, whether directly or by bonding jumper, and if any one of those were to be considered "primary", I'd say it is the one which has no maximum GEC size exemption under 250.66.
I always apply it that way, but NEC doesn't specifically tell us one or the other is a "primary" electrode either. The fact the water pipe needs supplemented makes that one a little less clear, what if we had water pipe and a concrete encased electrode and the service conductors in conjunction with 250.66 only required a maximum of 4 AWG? I think in that case you can run your GEC to either electrode and a bonding jumper to the other.
 

MannyBurgos

Senior Member
Location
Waukegan, IL
This was a question that was brought up recently. What i understand is if the GEC was ran to the ground rod 1st, then that GEC will have to be a full-sized conductor per T250.66. And if the water pipe was was ran 2nd, then 250.66 (A) would apply....
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Hello all. I am sure this has been bitten in the butt somewhere in here many times but here is my question: When you have (2) GEC's such as (1) ground rod and (1) water meter pipe in direct contact with earth for 10+ feet, which is considered your "primary" GEC?

In this case, where does bonding come into place besides the bonding bushing?

1. You only have 1 GEC. The GEC must be continuous or, if it must be spliced, done with an irreversible connection such as exothermic welding or a crimp ferule.

2. Ground rods are a supplementary earth ground source, which is why that portion of the GEC is only required to be #6cu

The water main provides a far better path to ground than do ground rods.

also, don't confuse your terminology:

GEC (Grounding Electrode Conductor): The conductor that interconnects grounding electrodes and the panel
GE (Grounding Electrode): The actual device that disperses electricity to ground (i.e. metal water pipe, ground rod, etc).
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
This was a question that was brought up recently. What i understand is if the GEC was ran to the ground rod 1st, then that GEC will have to be a full-sized conductor per T250.66. And if the water pipe was was ran 2nd, then 250.66 (A) would apply....
That is correct. If you use the ground rod for more than the sole connection then the grounding electrode conductor from the service panel must be sized to 250.66.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
1. You only have 1 GEC. The GEC must be continuous or, if it must be spliced, done with an irreversible connection such as exothermic welding or a crimp ferule.

2. Ground rods are a supplementary earth ground source, which is why that portion of the GEC is only required to be #6cu

The water main provides a far better path to ground than do ground rods.

also, don't confuse your terminology:

GEC (Grounding Electrode Conductor): The conductor that interconnects grounding electrodes and the panel
GE (Grounding Electrode): The actual device that disperses electricity to ground (i.e. metal water pipe, ground rod, etc).

You can have more than one GEC depending on how you want to connect to your electrodes. For example from the neutral a separate conductor run to the water pipe and two separate conductors run to each of two ground rods would be three GEC's.
 

kwired

Electron manager
Location
NE Nebraska
You can have more than one GEC depending on how you want to connect to your electrodes. For example from the neutral a separate conductor run to the water pipe and two separate conductors run to each of two ground rods would be three GEC's.
I like that explanation. We are only required to have one GEC, but in situation like described is there one that is the "primary" like what is asked in the OP?

I sort of think you just have three GEC's and all must be treated like they were the only GEC in that situation. You can remove all doubt by only running one GEC and then make bonding jumpers to the remaining elecrodes.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I like that explanation. We are only required to have one GEC, but in situation like described is there one that is the "primary" like what is asked in the OP?

I sort of think you just have three GEC's and all must be treated like they were the only GEC in that situation. You can remove all doubt by only running one GEC and then make bonding jumpers to the remaining elecrodes.

Yup, the NEC gives you option to run separate GEC's to each electrode or run one GEC and use bonding jumpers to create the GES, you can also use a combination of the two.

Also the NEC does not use the word primary when describing GEC's or electrodes so IMO we shouldn't use it either. :)
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Yup, the NEC gives you option to run separate GEC's to each electrode or run one GEC and use bonding jumpers to create the GES, you can also use a combination of the two.

Also the NEC does not use the word primary when describing GEC's or electrodes so IMO we shouldn't use it either. :)

Just because the NEC doesn't use a particular term doesn't mean others shouldn't to describe something. The fact is, the bond to water main is far more effective than ground rods. The ground rods are supplemental, making the water main the "primary" GE.
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
True, and it lands on the first GE, from there all others can be connected together with multiple jumpers.

Roger

You can use jumpers I suppose, but the connection must be irreversible. The best way is to use one continuous wire and thread it through all the lugs. If you can afford it, exothermic welding is the best to reduce ground impedance. It's almost as good as the original unbroken cross section.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Just because the NEC doesn't use a particular term doesn't mean others shouldn't to describe something. The fact is, the bond to water main is far more effective than ground rods. The ground rods are supplemental, making the water main the "primary" GE.

I don't see how it provides any clarity to the description of the electrode but to each his own. IMO if the NEC thought that an electrode needed further description as a "primary" electrode then they would have included that in the wording. What further confuses this discussion is when you have both the water pipe electrode and 20' of 1/2" rebar in the footing which constitutes a CEE, then which one is the primary?


You can use jumpers I suppose, but the connection must be irreversible. The best way is to use one continuous wire and thread it through all the lugs. If you can afford it, exothermic welding is the best to reduce ground impedance. It's almost as good as the original unbroken cross section.

Bonding jumpers do not require irreversible connections only the conductor that qualifies as the GEC does.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
You can use jumpers I suppose, but the connection must be irreversible.
Not true, see 250.50 and 250.53, there is no requirement that the jumpers be continuous or irreversible.


1100202225_2.jpg


Roger
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
I don't see how it provides any clarity to the description of the electrode but to each his own. IMO if the NEC thought that an electrode needed further description as a "primary" electrode then they would have included that in the wording. What further confuses this discussion is when you have both the water pipe electrode and 20' of 1/2" rebar in the footing which constitutes a CEE, then which one is the primary?

Point taken. I would say in that case they are both primary lol. Although, IMO, the rebar > water pipe.
 

Smart $

Esteemed Member
Location
Ohio
Point taken. I would say in that case they are both primary lol. Although, IMO, the rebar > water pipe.
If that were true, then why is a GEC that is sole connection to a CEE not required to be larger than #4 copper [250.66(B)]... yet there is no such exemption for an underground water pipe electrode?
 
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