Can You Solve This?

[admin]

Greetings Fast Trax® Fam-

Let's assume a 4000 Amp Service. You are being told to supply this service with (10) sets of 600 kcmil CU. What is the size of your GEC to your grounding electrode?

OK....Let's Go!!!!

[Ernesto]

Ok i will say the GEC should be 2/0 copper. NEC 2020 Table 250.66

[admin]

Greetings Ernesto,

No, 2/0 CU is not the answer. Remember it's (10) sets of 600 kcmil you are working with.

[admin]

Ok, since it is abundantly clear folks are not enthused about using these new message boards. I thought folks would LOVE the opportunity to post and learn but I guess the generation of today is just not engaging enough. As a result I will go ahead and answer the question.

(10) Sets of really mean nothing in this question. Since we are sizing the GEC (Grounding Electrode Conductor) and didn't say what type of electrode it is, you would logically turn to Table 250.66 for the answer and no math needed. Well, just a little math.

(10) Sets of 600kcmil is 600,000 cmils x 10 = 6,000,000 cmils and that is clearly greater than the 1100 given in the T250.66. So, the GEC never has to be larger than a 3/0 CU or 250 kcmil AL.

Keep in mind that if we had said "ground rods" then you would have simply gone to 250.66(A) and chose 6 AWG CU or 4 AWG AL and move on. But as you know I didn't give you a electrode type so you always default to Table 250.66

You're Welcome!

[Ernesto]

Thank you so much for the infromation.

[brian0104]

Thanks again Paul!