Cable tray system

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frenchcomp

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NEC 2005 Table 310.16 gives ampacities for power cables in raceway.
May I use this table for sizing cables within a metallic covered cable tray?
Having more than three current-carrying conductors in raceway, I'll use adjustment factors table 310.15(B)(2)(a)but I wonder if I can put conductors with different size together (i.e. 2x 3/0 AWG cables + 5x 10AWG cables adjacent in a same raceway)? Should I follow table B.310.11 (adjustment factors with 50% load diversity) as the one which cover different cable size?
 
Re: Cable tray system

Take a look at 392.11(A) (2005 version). It has something to say about ampacity in a covered tray. Also, the rules about more than three current-carrying conductors in a raceway do not take into account the size of any conductor. You count each as having the same impact on mutual heating as any other.

I would not recommend touching Table B.310.11. Look for the phrase ?load diversity? in other posts in this Forum, and you?ll see the difficulties inherent in trying to define ?load diversity.?
 
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