More than three current carrying conductors

[wyboy]

It is my understanding that the neutral (grounded conductor) on a four wire, 208, three phase feeder (wye) does not count as a current carrying conductor for derating when more than three current carrying conductors in a raceway. Is this correct?

 

[480sparky]

310.15( b )(4).

 

[chris kennedy]

Correct, but take a quick look at 310.15(B)(4), make sure that doesn't apply to you.

 

[jumper]

This is a good article to look at.

It discusses this issue and more.

http://ecmweb.com/nec/code-basics/electric_conductor_size_matters/