Single-conductor cables for 1/0 AWG and above

[gsalas]

Dear all,

I'm currently working in a project where the following design criteria are applied: "Low voltage cables shall be specified as single-conductors for cable sizes bigger to 1/0 AWG and multiconductors for cables smaller than 1/0 AWG". I have been looking in the NEC if there is any restriction to use multiconductors for sizes above 1/0 AWG and I can't find anything. I am aware that in some installations it might be easier to use "manageable" cable sizes to help in the routing process. However, I would like to know if (by standard or good engineering practices) there is something that recommends to use single-conductors from 1/0 AWG and on.

Thank you!

 

[don_resqcapt19]

That sounds like a cable tray project and large multiconductor cables are used in tray. However the weight and stiffness can be an issue for long runs.

 

[Julius Right]

It seems to me the NEC recommendations is to run the multiconductor cables and single core cables in separate cable trays.

The 3 conductor-cable overall diameter is less than a triplex of single

core cables. However, in a cable tray, even following NEC Art 392[22 and 80] the ampacity will be less[14-20%].