MC cable on tray VS NEC 310.15.b.2.a

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is it required adjusment factor on table 310.15(B)(2)(a) for more than 3 cable of 3C (3 phase) metal clad cable installed on cable tray, touching??.
or is it MC cable = raceway then no need reduction factor if no more than 3 current carryng conductor in one cable??

 

[Smart $]

Please see 392.11 for your situation. (A)(1) addresses your major concern, but it can be modified by other item requirements. If you have any additional questions, please post again...

 

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ok thanks i got it .
btw, in 392.11 (A)(3) state that no reducing factor required for multiconductor cable installed in single layer in uncovered tray if the spacing is maintaind. how about if these cable are toucing, is there reduction factor required?, because commonly we installed cable toucing each other on cable tray. on IEC standard it's describe clear about that, how about NEC.

 

[Smart $]

ok thanks i got it .
btw, in 392.11 (A)(3) state that no reducing factor required for multiconductor cable installed in single layer in uncovered tray if the spacing is maintaind. how about if these cable are toucing, is there reduction factor required?, because commonly we installed cable toucing each other on cable tray. on IEC standard it's describe clear about that, how about NEC.

The way I read it is if they are spaced one or more cable diameter of air between them, you can use the "free-air" Table B310.3 to determine ampacity. Otherwise (including touching ) you have to use Table 310.16.

While being able to use B310.3 doesn't alleviate termination-rating requirements on circuit ampacity, it does permit you to start at a slightly higher conductor ampacity in most cases. Note Table B310.3 is based on an ambient temp of 40?C, whereas Table 310.16 is based on 30?C... so make sure you adjust to the same temperature before comparing rated ampacities. For the Cu 90? column of Tabe B310.3, add/increase 10% to compare with Table 310.16 at 30?C. It's 13% for 75?C column.