Equipment Installed Under a Computer Room Raised Floor

[catchtwentytwo]

I need some help with this one.

An IT product manufacturer suggests that products similar to APC Rack Automatic Transfer Switch or
Pulizzi Engineering Dual-Input Auto Switching Systems

be used as a way of offering 2 supply sources for ?single-corded? computer hardware. These are designed for mounting in a typical server rack.

Problem is that this IT product manufacturer is suggesting they be mounted under a computer room raised floor(Article 645 compliant)to avoid space and cooling issues within the rack. I don?t see anything specific in Article 645 allowing or prohibiting this. I believe that unless they are 3RD party listed for this underfloor use, this is a violation.

One could look at Article 240.10 (Supplementary Overcurrent Protection) and say that these devices aren't required to be accessible but does this apply to these products? Other than making this an AHJ issue, what other NEC sections would address this "application"?

[ January 05, 2006, 10:28 AM: Message edited by: catchtwentytwo ]

 

[ron]

Re: Equipment Installed Under a Computer Room Raised Floor

Cords are not permitted under the raised floor unless they are DP rated, and almost all that I've seen are not. 645.5(D)(5).

 

[catchtwentytwo]

Re: Equipment Installed Under a Computer Room Raised Floor

Cords are not permitted under the raised floor unless they are DP rated, and almost all that I've seen are not. 645.5(D)(5).

Ron,

The branch-circuit conductors are installed per an approved method in. 645.5 (D)(2).

The branch-circuit supply conductors to receptacles or field-wired equipment are in rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, electrical metallic tubing, electrical nonmetallic tubing, metal wireway, nonmetallic wireway, surface metal raceway with metal cover, nonmetallic surface raceway, flexible metal conduit, liquidtight flexible metal conduit, or liquidtight flexible nonmetallic conduit, Type MI cable, Type MC cable, or Type AC cable. These supply conductors shall be installed in accordance with the requirements of 300.11.

I believe that 645.5(B)(1) covers the cord from the equipment to the underfloor receptacle.

B) Cord-and-Plug Connections. 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) Flexible cord and attachment plug cap not to exceed 4.5 m (15 ft).

Thanks,
John

 

[ron]

Re: Equipment Installed Under a Computer Room Raised Floor

645.5(B) takes care of general use of cords in a 645 environment. More specifically, to install cords below the raised floor, you must look at 645.5(D) which has additional restrictions.