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(A) Branch-Circuit Conductors
The branch-circuit conductors supplying one or more units of information technology equipment shall have an ampacity not less than 125 percent of the total connected load.
(B) Power-Supply Cords
Information technology equipment shall be permitted to be connected to a branch circuit by a power-supply cord.
  1. Power-supply cords shall not exceed 4.5 m (15 ft).
  2. Power cords shall be listed and a type permitted for use on listed information technology equipment or shall be constructed of listed flexible cord and listed attachment plugs and cord connectors of a type permitted for information technology equipment.
Informational Note: One method of determining if cords are of a type permitted for the purpose is found in UL 60950-1-2007, Safety of Information Technology Equipment — Safety — Part 1: General Requirements; or UL 62368-1-2012, Audio/Video, Information and Communication Technology Equipment — Part 1: Safety Requirements.
(C) Interconnecting Cables
Separate information technology equipment units shall be permitted to be interconnected by means of listed cables and cable assemblies. The 4.5 m (15 ft) limitation in 645.5(B)(1) shall not apply to interconnecting cables.
(D) Physical Protection
Where exposed to physical damage, supply circuits and interconnecting cables shall be protected.
(E) Under Raised Floors
Where the area under the floor is accessible and openings minimize the entrance of debris beneath the floor, power cables, communications cables, connecting cables, interconnecting cables, cord-and-plug connections, and receptacles associated with the information technology equipment shall be permitted under a raised floor of approved construction. The installation requirement shall comply with 645.5(E)(1) through (E)(3).
(1) Installation Requirements for Branch Circuit Supply Conductors Under a Raised Floor
(a) The supply conductors shall be installed in accordance with the requirements of 300.11.
(b) In addition to the wiring methods of 300.22(C), the following wiring methods shall also be permitted:
  1. Rigid metal conduit
  2. Rigid nonmetallic conduit
  3. Intermediate metal conduit
  4. Electrical metallic tubing
  5. Electrical nonmetallic tubing
  6. Metal wireway
  7. Nonmetallic wireway
  8. Surface metal raceway with metal cover
  9. Surface nonmetallic raceway
  10. Flexible metal conduit
  11. Liquidtight flexible metal conduit
  12. Liquidtight flexible nonmetallic conduit
  13. Type MI cable
  14. Type MC cable
  15. Type AC cable
  16. Associated metallic and nonmetallic boxes or enclosures
  17. Type TC power and control tray cable
(2) Installation Requirements for Electrical Supply Cords, Data Cables, Interconnecting Cables, and Grounding Conductors Under a Raised Floor
The following cords, cables, and conductors shall be permitted to be installed under a raised floor:
  1. Supply cords of listed information technology equipment in accordance with 645.5(B).
  2. Interconnecting cables enclosed in a raceway.
  3. Equipment grounding conductors.
  4. Where the air space under a raised floor is protected by an automatic lire suppression system, in addition to wiring installed in compliance with 725.135(C), Types CL2R, CL3R, CL2, and CL3 and substitute cables including CMP, CMR, CM, and CMG installed in accordance with 725.154(A) shall be permitted under raised floors.
    Informational Note: Figure 725.154(A) illustrates the cable substitution hierarchy for Class 2 and Class 3 cables.
  5. Where the air space under a raised floor is not protected by an automatic fire suppression system, in addition to wiring installed in compliance with 725.135(C), substitute cable Type CMP installed in accordance with 725.154(A) shall be permitted under raised floors.
  6. Listed Type DP cable having adequate fire-resistant characteristics suitable for use under raised floors of an information technology equipment room.
Informational Note: 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 1685-2015, 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. 0.3-2014, Test Methods for Electrical Wires and Cables.
(3) Installation Requirements for Optical Fiber Cables Under a Raised Floor
The installation of optical fiber cables shall comply with either of the following:
  1. Where the air space under a raised floor is protected by an automatic fire suppression system, optical fiber cables installed in accordance with 770.113(C), Types OFNR, OFCR, OFN, and OFC shall be permitted under raised floors.
  2. Where the air space under a raised floor is not protected by an automatic fire suppression system, only optical fiber cables installed in accordance with 770.113(C) shall be permitted under raised floors.
(F) 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 where installed under raised floors.
Informational Note: Securement requirements for raceways and cables not listed as part of, or for, information technology equipment are found in 300.11.
(G) Abandoned Supply Circuits and Interconnecting Cables
The accessible portion of abandoned supply circuits and interconnecting cables shall be removed unless contained in a raceway.
(H) 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:
  1. Date identified for future use
  2. Date of intended use
  3. Information relating to the intended future use

Related Code Sections

(C) Special Equipment, Interconnecting Cables
Separate information technology equipment units shall be permitted to be interconnected by means of listed cables and cable assemblies. The 4.5 m (15 ...