This issue causes me no end of grief. The whole idea of a raised floor has been wrecked by the NEC, and NEC 645 doesn't provide enough relief. How many of you have seen power cable or interface cables with a DP listing? I've never seen one. I suppose I could buy the cable and make up some, but I shouldn't have to. The interface cables are many times impossible to make up ourselves (proprietary connectors). What we've done in most of our 645 areas is to put 5" holes in some floor tiles and then mount a receptacle box on unistrut so it is directly under the hole. This way, only the cord cap is "under the floor" and only for about an inch.
The other thing that burns me up is that liquidtight flex is not allowed under our floors unless it is secured every 4 (?) feet. This again defeats the purpose of why you want a raised floor computing lab area. Fortunately, we have a contractor that is allowed to make UL Listed IT cable assemblies, so they do basically what we would do with the flex, but they can put a UL label on it.
Are any of you required to secure your phone or network cabling under the floor? I can't seem to find a code section that covers it. I used rip ties to every other floor post, and the inspector didn't seem to like that.
These inspectors don't seem to care that the layout of our computing rooms is constantly changing.
