Cable Trays Cable Derating

[MagnusElec]

Based on NEC 310.15(B)(2)(a) Exception No. 2 and 392.11(A)(1), I've concluded that no derating due to grouping is required for three-conductor 0-600V power cables installed in a cable tray; regardless of the number of cables as long as the fill is not exceeded; in a single vertical layer; and without separation distance.

Is this correct? (The situation is different for medium voltage cables).

Thanks

 

[wareagle]

I believe you would have to consider 392.11 A 1,2 and 3.