3 phase underground

[arnettda]

When trenching in underground three phase. My supplier does not sell a cable system of 350-350-350-4/0 just 2 350's and a 4/0. Can I use that and then add a single conductor 350 to it or should I use all single conductors. It would be cheaper to do it using the urd cable but I am wondering about the grouping of conductors and if that would matter.

 

[ActionDave]

If it is in the same ditch I don't see a problem with the added wire, I've done it.

 

[ptonsparky]

Group them as close as possible if you are worried. We have done it.

some one out there can probably tell how wrong it is.

 

[JFletcher]

here you go

Should be able to get lengths > 100'

300.3B allows adding another 350mcm in a trench