supply conductors shall be installed in accordance with the requirements of 300.11.
(3) Supply cords of listed information technology equipment in accordance with 645.5(B).
(4) Ventilation in the underfloor area is used for the information technology equipment room only, except as provided in 645.4(2). The ventilation system shall be so arranged, with approved smoke detection devices, that upon the detection of fire or products of combustion in the underfloor space, the circulation of air will cease.
(5) Openings in raised floors for cords and cables protect cords and cables against abrasion and minimize the entrance of debris beneath the floor.
(6) Cables, other than those covered in (D)(2) and those complying with (D)(6)(a), (D)(6)(b), or
(D)(6)(c), shall be listed as Type DP cable having adequate fire-resistant characteristics suitable for use under raised floors of an information technology equipment room.
a. Interconnecting cables enclosed in a raceway.
b. Interconnecting cables listed with equipment manufactured prior to July 1, 1994, being installed with that equipment.
c. Cable type designations shown in Table 645.5 shall be permitted. Green, or green with one or more yellow stripes, insulated single-conductor cables, 4 AWG and larger, marked "for use in cable trays" or "for CT use" shall be permitted for equipment grounding.
FPN: One method of defining fire resistance is by establishing that the cables do not spread fire to the top of the tray in the "UL Flame Exposure, Vertical Tray Flame Test" in UL 1685-2000, Standard for Safety for Vertical-Tray Fire-Propagation and Smoke-Release Test for Electrical and Optical-Fiber Cables. The smoke measurements in the test method are not applicable.
Another method of defining fire resistance is for the damage (char length) not to exceed 1.5 m (4 ft 11 in.) when performing the CSA "Vertical Flame Test
— Cables in Cable Trays," as described in CSA C22.2
No. 0.3-M-2001, Test Methods for Electrical Wires
and Cables.
Table 645.5 Cable Types Permitted Under Raised Floors
Article Plenum Riser General Purpose
336 TC
725 CL2P & CL3P CL2R & CL3R CL2, CL3 & PLTC
727 ITC
760 NPLFP & FPLP NPLFR & FPLR NPLF & FPL
770 OFNP & OFCP OFNR & OFCR OFN & OFC
800 CMP CMR CM & CMG
820 CATVP CATVR CATV
(E) Securing in Place. Power cables; communications cables; connecting cables; interconnecting cables; and associated boxes, connectors, plugs, and receptacles that are listed as part of, or for, information technology equipment shall not be required to be secured in place.
(F) Abandoned Supply Circuits and Interconnecting Cables. The accessible portion of abandoned supply circuits and interconnecting cables shall be removed unless contained in a metal raceway.
(G) Installed Supply Circuits and Interconnecting
Cables Identified for Future Use.
(1) Supply circuits and interconnecting cables
identified for future use shall be marked with a tag of sufficient durability to withstand the environment involved.
(2) Supply circuit tags and interconnecting cable tags shall have the following information:
a. Date identified for future use b. Date of intended use
c. Information relating to the intended future use