roof penetration question

[Znogard]

Roof top unit needs a feed, fire alarm cable and thermostat. Roof is penetrated by a liquidtight to disconnect and then is installed into the control cabinet in the unit. Normally a seperate roof penetration is made or the low voltage wiring is drilled into the inside cabinet area of the unit and the low voltage is snaked up inside the curbing.

My question is this...what if a larger liquidtight was used and a small liquidtight was pulled inside the larger one in addition to the branch circuit condutors. The smaller raceway is drilled through the junction box in the building. A connector penetrates the JB so the low voltage wires are isolated from the feeders all the way to the control cabinet. At the disconnect the raceway continues through to the cabinet

This would eliminate the need for a seperate roof penetration

I realise this is odd but is this legal? I have seem low voltage wires isolated in a wireway with a liquidtight raceway but never a raceway inside of a raceway

 

[kwired]

I just replied to a similar question.

See this thread

I think it is not acceptable but installing a sleeve with two separate cables or even raceways within the sleeve would be acceptable. They would need to separate somehow before entering the unit or the disconnect, as the FA cable is likely not allowed in the disconnect or the power component section of the unit.