Terminal Rating and Conductor Rating

[beanland]

480V, 255MCA chiller, with 75C lugs. I propose six 1/0 Cu THHN in 2" EMT. 1/0 Cu 90C rating is 170A. Two circuits derated by 80% provide 272A, adequate for load. I then say 1/0 Cu at the terminals is not in a raceway so the 80% does not apply. Each 1/0 Cu 75C is rated 150A. I have 300A capability so adequate. I say wire in raceway ay 90C where adjustment required and wire in enclosure at 75C where no adjustment is required.

Inspector says that since lugs are 75C rated, the wire must use the 75C rating and the 80% adjustment factor in the raceway.

Can anyone cite an NEC section that says that wire in a raceway must be rated based on the termination temperature rating?

 

[kpepin]

110.14(c) says you can (2005 code)

 

[augie47]

the way I read 110.14, you are correct and the inspector is wrong

 

[beanland]

Terminations

Terminations

It looks like 2005 NEC 110.14(C)(1)(b)(2) is governing. As long as I use the 75C rating at the termination, all is fine.

Thanks!