cable tray fill calc w/barrier

[iGwt]

I have a 30” wide ladder type metallic cable tray with a single barrier located as to provide a 12” section and 18” section. The 18” section contains 600V and less rated multiconductor power cables. The 12” section contains multiconductor instrument and control cabling. My question is, in your opinion, when calculating the allowable cable fill area for the two sections is it acceptable to utilize Article 392.9(B) of the NEC/CEC for the 12” instrument and control cabling section which allows for fill no greater than 50% of the interior cross sectional area, and utilize Table 392.9 for the 18” power cable section which states for an 18” tray the maximum cross sectional area is 21 in2?

 

[rcw retired EE]

That is the way I do it. Treat them as two separate trays each with their own allowable fill.