GEC sizing to a ground rod

[Dennis Alwon]

Why does the water pipe require a #4? Doesn't 250.66A come into play again as connection to a rod, pipe, or plate electrode? I am not trying to play devils advocate here. just trying to further understand. I feel I am thinking way too hard on this and perhaps should just drink my coffee.

Yes T. 250.66 states what size grounding electrode conductor with exceptions as stated before. T. 250.102 is for the bonding jumpers. Any conductor connected to the grounding electrode conductor would be the bonding jumpers and the Table 250.102 is almost identical to t250.66. The water pipe has no exceptions so it must be #4 in this case. Since the wire (grounding electrode conductor) to the rod can be #8 but only if there isn't any bonding jumpers from the rod.

 

[xformer]

It's confusing but the pipe in 250.66(A) is not a water pipe electrode. It's a piece of pipe used like grounding rod.

AHHH.... Volia - meaning, and then I found out. Thanks Infinity.

 

[infinity]

AHHH.... Volia - meaning, and then I found out. Thanks Infinity.

Yes that section is very confusing. Glad that it makes sense now.

 

[roger]

The wording should include "driven" it would help make it clear that it is not a water pipe.

 

[don_resqcapt19]

The wording should include "driven" it would help make it clear that it is not a water pipe.

Looking forward to reading your PI to make this clarification for the 2026 code

 

[don_resqcapt19]

Think of (A) as an exception to T. 250.66. There is other exceptions also as in CEE

This is an example of where I think the code was easier to understand when these were written as actual exceptions. The style manual does not like the use of exceptions, so many former exceptions were rewritten into "positive" language like they did here.

 

[roger]

Looking forward to reading your PI to make this clarification for the 2026 code

Don't hold your breath.