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Thread: Cable tray sizing for 4160v and 480v

  1. #1
    Join Date
    Feb 2003
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    Nevada
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    Cable tray sizing for 4160v and 480v

    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

  2. #2
    Join Date
    Jun 2006
    Location
    Ohio
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    12,653
    Quote Originally Posted by blues View Post
    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.
    I'll never get there. No matter where I go, I'm always here.

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