DP cable requirement under RAF?

[ryanee24]

I have a situation where we are feeding an electrical room with cables in tray under a raised access floor. We are feeding switchboards and UPS modules in this room. The area under the RAF is pressurized and used to cool the equipment from below via grills in the floor tiles. The HVAC units are located in the room, and none of the air is shared with any adjacent areas. All I can find in the code for this is Article 645 - Information Technology rooms. But this room is not an IT room, it is an electrical equipment room. Do the feeder cables need to be DP rated? Or can they be THHN/THWN CT rated cables(vertical flame test).

P.S. We have underfloor smoke detection wired to shunt trip the main feeds to the HVAC units in the event that smoke is detected.

Any advice is appreciated.

 

[tom baker]

Re: DP cable requirement under RAF?

The way I read Art 645 is a DP cable can only be used in a Art 645 application. If your equipment and room do not meet the requirements of Art 645, the it becomes a chapter 3 wiring method.

[ April 24, 2004, 12:02 PM: Message edited by: tom baker ]

 

[ron]

Re: DP cable requirement under RAF?

If you are not interested in the leniencies as permitted by article 645 and the then required compliance with 645.2, then you will need to refer to 300.22(C)(1) and 392.4.
Generally you can't do what you want to do unless you use a cable that is "specifically listed for the use", which is a judgment made by the AHJ.