250.64(f)

[mikehughes8]

I'm came across this article and it's been a source of confusion for me. It says I can run the grounding electrode conductor to one or more electrodes individually.
Does this mean I can have more than one grounding electrode conductors?

Secondly, this article states "the grounding electrode conductor shall be sized for the largest grounding electrode conductor required among all electrodes connected to it"

How does an electrode influence my grounding electrode size. I thought this was determined by my ungrounded conductors. Obviously I'm reading more into this than I should.

Please help!

 

[tom baker]

Different GEs have varying GEC sizes, refer to Table 250.66. If you hit a water pipe it may be a larger GEC than a ground rod, example 4 awg to a water pipe but section 250.66 states the max size to a ground rod is 6 awg. You size the GEC per the ungrounded conductor and then look at section 250.66 to see if it can be smaller. Table 250.66 is "full size" values and section 250.66 modifies.

 

[raider1]

Does this mean I can have more than one grounding electrode conductors?

Yes you can run a GEC to each electrode if you want.

Secondly, this article states "the grounding electrode conductor shall be sized for the largest grounding electrode conductor required among all electrodes connected to it"

What this section is saying is that if I have a GEC that runs to a ground rod and then on to say a water pipe electrode, the the GEC run to the ground rod must be sized for the water pipe electrode and you can't use section 250.66(A) that says the sole connection to the ground rod doesn't have to be larger than a #6 copper wire or #4 aluminum wire.

Hope this helps,

Chris

 

[Dennis Alwon]

Yes you can run a GEC to each electrode if you want.
What this section is saying is that if I have a GEC that runs to a ground rod and then on to say a water pipe electrode, the the GEC run to the ground rod must be sized for the water pipe electrode and you can't use section 250.66(A) that says the sole connection to the ground rod doesn't have to be larger than a #6 copper wire or #4 aluminum wire.Chris

Interesting because article 250.64(A) states that aluminum shall not be terminated within 18" of the earth.

 

[raider1]

Interesting because article 250.64(A) states that aluminum shall not be terminated within 18" of the earth.

I guess that is why they make 10 foot ground rods.

Chris

 

[Dennis Alwon]

I guess that is why they make 10 foot ground rods.

Chris

I didn't think about that but that would be real attractive. 2' feet sticking out of the ground with aluminum. Yuck. The cost of a 10 foot ground rod you could put a piece of copper in and bury it with an 8' rod. My preference anyway.

 

[Dennis Alwon]

I didn't think about that but that would be real attractive. 2' feet sticking out of the ground with aluminum. Yuck. The cost of a 10 foot ground rod you could put a piece of copper in and bury it with an 8' rod. My preference anyway.

Also see Article 250.53 (A)

 

[mikehughes8]

Ok..I understand now. thanks