250.66 sizing electrode grounding conductor

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cocodrilo

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Can anyone tell me if the exception in 250.66(a) thru (c) that refers you back to 250.52 (A)5 (A)6 mean that you do not have to go larger than # 6 copper if connecting to the 8ft grounding rod?
 

cocodrilo

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thanks , but why do you typically size a number 4 awg cu for a 200 amp single phase service if you can use the exception.
 

raider1

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So if the other electrode in combo with the ground rod is a cold water pipe, this exception does not apply?

The exception only applys to the portion of the GEC that is the SOLE connection to the ground rod.

So if I have a water pipe the GEC run to the water pipe must be sized in accordance with Table 250.66, but if I run a bonding jumper from the water pipe to a ground rod or run a separate GEC only to the ground rod then those conductors never need to be larger than #6 copper.

Chris
 

infinity

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So if the other electrode in combo with the ground rod is a cold water pipe, this exception does not apply?

That depends on the installation. If you ran a #4 GEC to the water pipe you could tap off that with a #6 to the ground rod. The ground rod in that example would not required the conductor to be larger than #6.
 

iwire

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I don't know what Larry is talking about. :grin:


I agree with the others and only want to add not to forget that 6 AWG needs protection from damage while 4 AWG or larger does not.
 

Dennis Alwon

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Has anyone ever heard that stranded wire is not allowed to the ground rod? I have never used stranded but I heard that people are cited for this because stranded is not resistant to corrosive conditions. So what is a corrosive condition-- underground????
 

infinity

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Has anyone ever heard that stranded wire is not allowed to the ground rod? I have never used stranded but I heard that people are cited for this because stranded is not resistant to corrosive conditions. So what is a corrosive condition-- underground????

I have never used anything but stranded. It's code compliant to use either.
 

Dennis Alwon

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Here is what they are citing.

250.62 Grounding Electrode Conductor Material.
The grounding electrode conductor shall be of copper, aluminum, or copper-clad aluminum. The material selected shall be resistant to any corrosive condition existing at the installation or shall be suitably protected against corrosion. The conductor shall be solid or stranded, insulated, covered, or bare.
 

infinity

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Here is what they are citing.

To me that sounds bogus unless they can provide some empirical data stating otherwise. I would go out on a limb and say that the copper will last longer than the ground rod even if it's stranded. :)
 

Dennis Alwon

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To me that sounds bogus unless they can provide some empirical data stating otherwise. I would go out on a limb and say that the copper will last longer than the ground rod even if it's stranded. :)

I have seen stranded with corrosion between the strands when outdoors. The part that bothers me is the code says okay then adds this corrosion thing. Why not just say stranded indoors-- what would happen to all those engineers that spec 3/0 to the ground rod?:)
 

Dennis Alwon

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I guess I am trying to make sense of 250.62. It tells us we can use copper, stranded or solid, yet it also states to select a material that is resistant to corrosion condition. How does one determine what a corrosive condition is? I suspect in a pool area with chlorine gas would be one of those condition but how do I know if stranded is not conducive for that situation. Could you encapsulate your conductor , after the install, with something to protect it?

I've always read that copper oxide is conductive.

Can I dream? :grin:

Dream on....
 
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