Question on wireways 376.22 and derating 310.15 (b) 2

[KWH]

I do not have to derate with 30 or less conductors in a trough but if there is 34 which percentage in the derating table do you use,

31 thru 34 or 4 thru 6.

Thanks

 

[infinity]

The requirement for derating is for 30 CCC's and above, not 30 conductors. You would derate for the total number of CCC's not only the ones in excess of 30.