2000 amp servcie

[augie47]

Trying to get an E/C out of a bind...
He has a 2000 amp M/B service and was under the impression that he could install a set of 500 Cu. in his each of his 3" Sch 80 PVC conduits.
Once he was informed his 500s would not be sufficient for the 200 amp service, we were looking for a way to save the install.

Unless I made a mistake, he could install (6) 250s with a 1/0 Neutral in each conduit.
(6)250s would derate to 232 amps. 10 conductors exceed his 2000 amp requirement.
(6)250 THWN-2 + (1) 1/0, in each 3" Sch 80 {(6) X .3970 = 2.382 + (1) .1855 = 2.5675}

3" Sch 80 allows 2.577

anyone see an error in the plan ?

 

[steve66]

For derating, I get:

250KCM's good for 255 amps.

Derate at 80% is 204 amps?

And the neutral is really downsized - only 750 amps before derating.

Maybe the adjustments on the breaker could be set for 1900 amps? That would allow the 5 sets of 500's.

 

[david luchini]

Trying to get an E/C out of a bind...
He has a 2000 amp M/B service and was under the impression that he could install a set of 500 Cu. in his each of his 3" Sch 80 PVC conduits.
Once he was informed his 500s would not be sufficient for the 200 amp service, we were looking for a way to save the install.

Unless I made a mistake, he could install (6) 250s with a 1/0 Neutral in each conduit.
(6)250s would derate to 232 amps. 10 conductors exceed his 2000 amp requirement.
(6)250 THWN-2 + (1) 1/0, in each 3" Sch 80 {(6) X .3970 = 2.382 + (1) .1855 = 2.5675}

3" Sch 80 allows 2.577

anyone see an error in the plan ?

Looks good to me.

I think you can go to #4/0 THWN-2 though.

 

[augie47]

Looks good to me.

I think you can go to #4/0 THWN-2 though.[/QUOTE

Thanks.
I did not even try that :thumbsup:

 

[augie47]

For derating, I get:

250KCM's good for 255 amps.

Derate at 80% is 204 amps?

And the neutral is really downsized - only 750 amps before derating.

Maybe the adjustments on the breaker could be set for 1900 amps? That would allow the 5 sets of 500's.

I believe by using THWN-2, I'm allowed to derate at the 290 amp rating.
Mute point after davids post// just sayin...

 

[steve66]

I believe by using THWN-2, I'm allowed to derate at the 290 amp rating.
Mute point after davids post// just sayin...

Oh, yes, of course. It may be a mute point, but thanks for posting that. Otherwise I'd still be scratching my head trying to figure out what I did wrong.

And now that I look at it again, 10 sets at even 204 amps would get you to 2000 amps.