Phase conductors and derating

[Shockedby277v]

I know that you use to be able to run all of a phase into a single pipe if the entire run was PVC with no metal but I don't if the '14 code changed anything with it. I can't find the code article. Here's what I want to do.

I would like to run to my transformer from the service with 4 - 6" pipes (PVC). A pipe for each phase and neutrals. Vs running 10 - 4" pipes. There is question #1.

My second question is. Do I need to derate these? I plan on running 10 - 600 Cu per phase for a 4000 amp service.

Thanks

 

[Carultch]

I know that you use to be able to run all of a phase into a single pipe if the entire run was PVC with no metal but I don't if the '14 code changed anything with it. I can't find the code article. Here's what I want to do.

I would like to run to my transformer from the service with 4 - 6" pipes (PVC). A pipe for each phase and neutrals. Vs running 10 - 4" pipes. There is question #1.

My second question is. Do I need to derate these? I plan on running 10 - 600 Cu per phase for a 4000 amp service.

Thanks

Given 10 CCC's in a single conduit, you do have to derate for bundling, and possibly with a basic derate for ambient temperature as well.

 

[kwired]

I know that you use to be able to run all of a phase into a single pipe if the entire run was PVC with no metal but I don't if the '14 code changed anything with it. I can't find the code article. Here's what I want to do.

I would like to run to my transformer from the service with 4 - 6" pipes (PVC). A pipe for each phase and neutrals. Vs running 10 - 4" pipes. There is question #1.

My second question is. Do I need to derate these? I plan on running 10 - 600 Cu per phase for a 4000 amp service.

Thanks

See 300.3(B) and 310.10(H) for rules on parallel conductors.

Yes you can run all one phase in one non metallic raceway in your application. You still need to adjust ampacity when there is more then 3 current carrying conductors in a raceway though, and 10 conductors gives you a 50% adjustment - which would probably hurt your wallet on your project those 600 Cu are only good for 237.5 amps with 10 in a raceway, if you can get to 9 conductors then 70% adjustment applies, but would still need to be much larger conductors to get to 4000 amps.