Multiple grounding electrodes -- connecting wire sizes

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fmtjfw

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Fairmont, WV, USA
The following is from a code panel yesterday:

My grounding electrode system consists of a water pipe, a UFER, and a ground rod. My service conductors are 500kcmil copper. Can I run a 1/0 CU grounding electrode conductor to the water pipe, then a #4 copper conductor from the water pipe to the UFER, then a #6 copper from the UFER to the ground rod?

The answers were yes and no. What do you guys think?
 
What was the reason for the no, sounds legal.

25050.jpg
 
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fmtjfw said:
The following is from a code panel yesterday:

My grounding electrode system consists of a water pipe, a UFER, and a ground rod. My service conductors are 500kcmil copper. Can I run a 1/0 CU grounding electrode conductor to the water pipe, then a #4 copper conductor from the water pipe to the UFER, then a #6 copper from the UFER to the ground rod?

The answers were yes and no. What do you guys think?
Click to expand...

My answer would be yes. However, the #6 would have to be protected in some way.
 
Engineer's answer

Engineer's answer

jumper said:
What was the reason for the no, sounds legal.

25050.jpg
Click to expand...

The no answer came from an engineer on the panel. He said that all conductors needed to be 1/0 since 250.66(A)&(B) both stated "that portion of the conductor that is is sole connection to the grounding electrode" invalidated the two smaller conductor exceptions. Basically that the #4 conductor had to carry not only the current to the UFER but also to the ground rod. He didn't extend that argument to the 1/0 since the table said it was sufficient for any GEC.

His argument depends on what "sole" means.
 
fmtjfw said:
The no answer came from an engineer on the panel. He said that all conductors needed to be 1/0 since 250.66(A)&(B) both stated "that portion of the conductor that is is sole connection to the grounding electrode" invalidated the two smaller conductor exceptions. Basically that the #4 conductor had to carry not only the current to the UFER but also to the ground rod. He didn't extend that argument to the 1/0 since the table said it was sufficient for any GEC.

His argument depends on what "sole" means.
Click to expand...

The fact that since you have a water pipe and UFER GES in place means that the whole rod connection(s) is nothing but extra.

EE is wrong IMO. I believe the purpose of this section is more in line with something like that you cannot run a #4 to a UFER and then then a larger jumper, ie: #2 to a ground ring, and be compliant.
 
fmtjfw said:
The no answer came from an engineer on the panel. He said that all conductors needed to be 1/0 since 250.66(A)&(B) both stated "that portion of the conductor that is is sole connection to the grounding electrode" invalidated the two smaller conductor exceptions. Basically that the #4 conductor had to carry not only the current to the UFER but also to the ground rod. He didn't extend that argument to the 1/0 since the table said it was sufficient for any GEC.

His argument depends on what "sole" means.
Click to expand...

I think he does not understand English very well.
 
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