Ground rod is only means of grounding

[megawatts52]

i have a question. doing a 5 bank meter 400 amps. this is in existing building, a tree fell on part of the building where the electrical equipment was. their is no water pipe that's metallic. no way to ground the footers. so i do know i must install the ground rods 2 of course. since the largest ungrounded conductor size id 500 kcmil al, i know the conductor forr the grounding is a 1/0. code says no larger than #6 to ground rods. my question is will it hurt to make the ground rods as the mail grounding and use the 1/0, or to do as the code says? thank you.

 

[LarryFine]

Welcome to the forum.

For rods, etc., #6cu is the largest required (even if the only electrodes), not the largest allowed.

You may use a larger wire, but there is absolutely no advantage to doing so, only wasted money.

 

[petersonra]

i have a question. doing a 5 bank meter 400 amps. this is in existing building, a tree fell on part of the building where the electrical equipment was. their is no water pipe that's metallic.

What was the old service connected to?

no way to ground the footers.

I don't think it matters if there is a way to do it or not. I think if it is there you have to use it. What was the old service connected to?

so i do know i must install the ground rods 2 of course. since the largest ungrounded conductor size id 500 kcmil al, i know the conductor forr the grounding is a 1/0. code says no larger than #6 to ground rods. my question is will it hurt to make the ground rods as the mail grounding

What is mail grounding?

and use the 1/0, or to do as the code says? thank you.

No one cares, including the code or the electrons.

 

[ptonsparky]

mail vs main

Spell check, I believe.

 

[petersonra]

mail vs main

Spell check, I believe.

What is main grounding?

 

[infinity]

since the largest ungrounded conductor size id 500 kcmil al, i know the conductor forr the grounding is a 1/0. code says no larger than #6 to ground rods. my question is will it hurt to make the ground rods as the maiN grounding and use the 1/0, or to do as the code says?

Some terminology, the conductor is a GEC (grounding electrode conductor). There is no "main grounding", you need to establish a GES (grounding electrode system) which is your case will be two ground rods. Some think of one type of electrode as the main electrode (like the water pipe) because it requires to be supplemented but the NEC does not use the term main when describing different electrodes. As mentioned if the rods are your GES then the largest GEC to the rods is #6.

 

[hillbilly1]

mail vs main

Spell check, I believe.

What is main grounding?

The op is probably talking about three ground rods connected in a delta fashion. Engineers usually spec that for commercial installs.