What size equipment grounding conductor?

[fbhwt]

I am in dispute over the size equipment grounding conductor needed. Service is 1000a ,208v, 3ph
3 sets of 4-400mcm from 1000a service disconnect to 1000a transfer switch. I say it should be 2/0 copper or 4/0 alu according to 250.122, disconnect is fused at 1000a

 

[augie47]

I agree. The other opinion is ????

 

[ibew441dc]

I am in dispute over the size equipment grounding conductor needed. Service is 1000a ,208v, 3ph
3 sets of 4-400mcm from 1000a service disconnect to 1000a transfer switch. I say it should be 2/0 copper or 4/0 alu according to 250.122, disconnect is fused at 1000a

It sounds like you got it down.....but just remember the EGC has to be full size in each of the raceways in parallel.

 

[fbhwt]

I was told I was not looking in the right place, something about 250.66, which we know is for sizing grounding electrode conductor.

 

[ibew441dc]

I was told I was not looking in the right place, something about 250.66, which we know is for sizing grounding electrode conductor.

The short answer for you to back your self up(because you are correct) is to take a look at 250.102(C) and (d)

 

[fbhwt]

Thanks to you both for the help!

 

[charlie b]

Once you are beyond the service disconnecting means, table 250.66 is no longer a player. I agree with the others: you had it right.