Multiple MV Cables in Same Raceway

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cpe

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Is there a code issue about multiple MV cables (multiple motor feeders) in the same raceway? I have searched and cannot find it. I know the cables would require derating and I feel this is an impractical way to route the cables.
The NEC tables do not get into multiple MV conductors in raceway nor do they discuss multiple circuits (or at least I did not find it).
Any advice?
 
Re: Multiple MV Cables in Same Raceway

Good question. All I can offer is that the de-rating values of Table 310.15(B)(2)(a) would not apply to cables rated over 2000 volts, and that I cannot find a similar table that does apply. However, I have seen cable trays that contained several runs of armored MV105 cables that served several 4160 volt loads. I do not know how the ampacity issue was addressed.
 
Re: Multiple MV Cables in Same Raceway

Thanks for trying to look.
I have run 13.8KV cables in a cable tray, actually 6 different feeders in CLX cable (MC type but continuous),which actually acts like a conduit and is almost as difficult.
Using multiple circuits in a tray on that level requires you maintain atleast 6" cable separation to avoid the requirement of derating. That means that each CLX 3 conductor run was spaced 6" from the next.
Thanks
CPE
 
Re: Multiple MV Cables in Same Raceway

Help me, why the 6" separation? I use 392.12 for number of conductors in tray & ampacity of conductors.
 
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