Question on de-rating conductors

[KWH]

I have 4 to 6 conductors in a conduit, when de-rating do you use the 90degree chart for thhn

 

[david luchini]

I have 4 to 6 conductors in a conduit, when de-rating do you use the 90degree chart for thhn

Yes, you can use the 90 degree rating when applying an adjustment factor for number of conductors in a raceway.

See 110.14(C).

 

[kingpb]

Assuming those are current carrying conductors rated for continuous operation, I concur.

 

[infinity]

Assuming those are current carrying conductors rated for continuous operation, I concur.

Care to explain this?

 

[kingpb]

Care to explain this?

4 conductors - 3 phase circuit with ground; i.e. 4 conductors

6 conductors - 3 phase conductors, neutral, ground, and isolated ground; 6 conductors

In both cases only 3 current carrying conductors.