Flex cord on raised floor

[smccluer]

The site is a large IT room (data center)fully compliant with Art 645. From a Power Distribution Unit, each branch circuit cable is distributed under the 30" raised floor in flex LT metal conduit, terminating in a receptacle box as permitted by Art 645.5(D). The equipment to be plugged into the receptacle sits above it on the raised floor and comes equipped with a ten-foot cord.

QUESTION. Can I plug the cord into the receptacle without running it in conduit? It is not marked DP cable.

Art 400.8(2) seems to prohibit "where run through holes in... floors, (unless specifically permitted in 400.7). However, 400.7(A)6)permits use of flex cord "for connection of utilization equipment to facilitate frequent interchange," and 400.7(A)(9) permits Data Processing cables as permitted by 645.5. If I look there, I find "the data processing system shall be permitted to be connected to a branch circuit by any of the following means listed for the purpose:"
"(1) flex cord & attachment plug cap not to exceed 15 ft"
"(2) cord set assembly. Where run on the surface of the floor, they shall be protected against physical damage."

So it seems to me to be permitted as long as the cord is not laying on the surface of the floor and it is part of the listed IT equipment. But AHJ says no. Who's right?

 

[earlydean]

Re: Flex cord on raised floor

"the data processing system shall be permitted to be connected to a branch circuit by any of the following means listed for the purpose:"

Doesn't that tell it all? The cord is not labled for use in the DP room. Unless you can show the AHJ the cord is OK (literature from the manufacturer?) he is right. The NEC only requires the cord to be listed, not labled, maybe it is in the UL green book?

 

[coreyd]

Re: Flex cord on raised floor

Is it an accessibility issue? The plug is the equipment's "disconnecting means" after all. But as the code tells us, it's all up to the AHJ. I did a similar installation a few months ago in northern Illinois, and had no problems passing inspection. The only difference is that I ran EMT from the supply to the receptacles.

 

[iwire]

Re: Flex cord on raised floor

As long as this room meets all the requirements of 645.2 you are permitted to use cords on, under and through the floor.

645.5 gives all the specifics of what you can and can not do with cords.

645 modifies the rules for cords in 400, look at 90.3.

Plugs under the floor serving the equipment on the floor by means of cord is how it is done most of the time in this area.

It is important to note that the installation of the raised floor is only part of the requirements that allow use of cords in this manner.

You must have separate ventilation systems, power disconnect switch etc.