ground wire sizing

[Stevenfyeager]

Some utilities require a #4 Cu ground wire here in IN. for a 200 amp house service. But I thought #6 is all the bigger it needs to be. NEC, where? table 250.66 would say #4 right? Thank you.

 

[augie47]

The utilities here require a minimum #4 grounding electrode conductor for their required ground rod regardless of NEC Code.
Their power, their rules

 

[infinity]

Some utilities require a #4 Cu ground wire here in IN. for a 200 amp house service. But I thought #6 is all the bigger it needs to be. NEC, where? table 250.66 would say #4 right? Thank you.

Which grounding electrode conductor are you referring to? The size may change depending on the type of the electrode.

 

[Stevenfyeager]

Which grounding electrode conductor are you referring to? The size may change depending on the type of the electrode.

to ground rods

 

[infinity]

to ground rods

Then #6 is all that's required.

 

[Stevenfyeager]

Then #6 is all that's required.

For 400 amp service, including two 200 amp panels, still # 6 ?

 

[ActionDave]

For 400 amp service, including two 200 amp panels, still # 6 ?

Look at 250.66(A)

 

[infinity]

For 400 amp service, including two 200 amp panels, still # 6 ?

As I stated earlier different electrode have different GEC requirements. For example the largest GEC required (regardless of the service size) to a ground rod is #6, to a CEE is #4, and to a water pipe is #3/0.

 

[Stevenfyeager]

As I stated earlier different electrode have different GEC requirements. For example the largest GEC required (regardless of the service size) to a ground rod is #6, to a CEE is #4, and to a water pipe is #3/0.

Thanks, I see 250.66 A now.

 

[jaggedben]

One rod only requires #6. Two rods requires a full size GEC. If you have two ground rods on a 200A service then the GEC to the first one needs to be typically #4. Your bonding jumper between the first and second rod can be #6.

 

[ActionDave]

One rod only requires #6. Two rods requires a full size GEC. If you have two ground rods on a 200A service then the GEC to the first one needs to be typically #4. Your bonding jumper between the first and second rod can be #6.

The language in 250.66(A) got butchered up when they added the words "sole connection" but the understanding was it would make it clearer that you don't need anything larger than #6 for ground rods. 2017 code made an attempt to clarify this.

 

[jaggedben]

The language in 250.66(A) got butchered up when they added the words "sole connection" but the understanding was it would make it clearer that you don't need anything larger than #6 for ground rods. 2017 code made an attempt to clarify this.

Ah, I see. We're not on the 2017 here yet, that will be an improvement.

 

[DrSparks]

Wouldn’t #6 only apply when ground rods are supplemental GE?


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[ActionDave]

Wouldn’t #6 only apply when ground rods are supplemental GE?


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Have you read 250.66(A)?

 

[augie47]

I agree a #6 is all that's needed regardless of the number of rods.
The "sole connection" wording was introduced in the event say someone wanted to go to the rod 1st and then from the rod to the water. IN that case the #6 would be a weak link in the chain

 

[don_resqcapt19]

Note that the original post said that the utility was requiring the 4AWG GEC, not the code. They can require things that are beyond what the code requires.