Feeder Derating

[steve holt]

Do you have to count the neutral in a four wire feeder as a current carrying conductor when considering derating?

 

[infinity]

Probably not. What is the load? Unless it's a data center chances are there are very few feeders that ever need the neutral to be counted as a CCC.

 

[bwat]

For the reference, see 310.15(B)(5)

 

[ron]

Probably not. What is the load? Unless it's a data center chances are there are very few feeders that ever need the neutral to be counted as a CCC.

Most data centers don't consider the neutral (grounded conductor) a CCC anymore. IT equipment has become more harmonic friendly due to equipment specific harmonic limits for European power supplies that get carried over to US equipment to limit SKUs.