Metallic Wireway vibration isolation

[zdbleam]

Hello,

I have a 12"x12" metallic wireway going to be connected to a large generator dogbox (enclosure on the generator that houses the output terminals). My company has historically used Durodyne, which is a flexible, cut to size ducting with neoprene fabric in the middle. This is not however UL listed for wireway, which has led to some issues with a customer. Apparently the Durodyne is pretty common for this kind of situation.

Looking at the major wireway manufacturers, they only go up to 8x8 for a flexible fitting. Can I use the 8x8 fitting with a 12" to 8" reducer? This would be larger than the max 20% fill for wireway required by NFPA 70: 376.22A, which makes me think it's a no. Otherwise, I'm not sure how to isolate the wireway from the generator's vibration.

Thanks,
zdbleam

 

[Raptor1963]

mcmaster-carr has a rectangular bellows similar to the 8x8....they work too.

 

[synchro]

You might split the cables equally between two flexible fittings and have the cables in a parallel arangement. You'd need to have the same number of sets of conductors in the two fittings. Each set would have a L1, L2, L3, N if required, and an EGC.