Cable tray sizing for 4160v and 480v

[blues]

I will try to word this question so it makes sense.

I have 4160v multi-conductor cables with 480v multi-conductors in the same ladder type ventilated cable tray. My first though was to size the tray based on 392.22(A)(1)(b). But after some thought I have spaced the 4160v cables per 392.80(B)(1) which then spaces cables in a single layer with maintained spacing of not less than on cable diameter between cables. I then subtracted that spacing from 36" width which is the tray size I am using. The remainder of the tray width I will use to determined if the tray size is adequate based on the sum of the cross-sectional areas of all cables smaller than 4/0 that do not exceed the maximum allowable fill area in column 1 of table 392.22(A) for the appropriate tray width.

Thanks,
Dan Craven

 

[Smart $]

I will try to word this question so it makes sense.

I have 4160v multi-conductor cables with 480v multi-conductors in the same ladder type ventilated cable tray. My first though was to size the tray based on 392.22(A)(1)(b). But after some thought I have spaced the 4160v cables per 392.80(B)(1) which then spaces cables in a single layer with maintained spacing of not less than on cable diameter between cables. I then subtracted that spacing from 36" width which is the tray size I am using. The remainder of the tray width I will use to determined if the tray size is adequate based on the sum of the cross-sectional areas of all cables smaller than 4/0 that do not exceed the maximum allowable fill area in column 1 of table 392.22(A) for the appropriate tray width.

Thanks,
Dan Craven

Assuming your 4160 cable cables are not Type MC, 392.20(B)(2) requires a barrier between the MV and LV cables. Though not explicitly stated, you apply 392.22(A)(1)(b) to width of the LV section... which is essentially what I believe you are saying.