600a + 400a service al conductor sizing

[bgelectric]

Hey everyone.
This came up recently and need some clarification.
Plans call for parallel 500mcm (no indication if cu or al) to a 3ph 600a service and a 3ph 400a service.
There are 2- 4" pvc conduits running to the services. The 600a has one 4" spare.
Looking at table 310.15b2a I can use parallel 350cu to the satisfy the 600a service and parrallel 3/0cu for the 400a service.
Also if looking at Al conductors I can use parallel 500al for the 600a service and parallel 250al for the 400a service.

Just want to make sure im on the right track.
Going by memory now i believe I can fit up to 7 - 500 xhhw into a 4" schedule 40 pvc so there are no issues there.

 

[infinity]

Hey everyone.
This came up recently and need some clarification.
Plans call for parallel 500mcm (no indication if cu or al) to a 3ph 600a service and a 3ph 400a service.
There are 2- 4" pvc conduits running to the services. The 600a has one 4" spare.
Looking at table 310.15b2a I can use parallel 350cu to the satisfy the 600a service and parrallel 3/0cu for the 400a service.
Also if looking at Al conductors I can use parallel 500al for the 600a service and parallel 250al for the 400a service.

Just want to make sure im on the right track.
Going by memory now i believe I can fit up to 7 - 500 xhhw into a 4" schedule 40 pvc so there are no issues there.

You might have an issue with derating if there are more than 3 CCC's in that one raceway.

 

[bgelectric]

Why do you say I might have an issue...?
Would there be a circumstance where it wouldnt be, or vice-versa?