ELECTRONIC COMPUTER/DATA

PROCESSING EQUIPMENT 645-1. Scope. This article covers equipment, power-supply wiring, equipment interconnecting wiring, and grounding of electronic computer/ data processing equipment and systems, including terminal units, in an electronic computer/data processing room. (FPN): For further information, see Protection of Electronic Computer/Data Processing Equipment, NFPA 75-1992 (ANSI). 645-2. Special Requirements for Electronic Computer/Data Processing Equipment Room. This article applies provided all the following conditions are met: (1) Disconnecting means complying with Section 645-10 are provided. (2) A separate heating/ventilating/air conditioning (HVAC) system is provided that is dedicated for electronic computer/data processing equipment use and is separated from other areas of occupancy. Any HVAC system that serves other occupancies may also serve the electronic computer/data processing equipment room if fire/smoke dampers are provided at the point of penetration of the room boundary. Such dampers shall operate on activation of smoke detectors and also by operation of the disconnecting means required by Section 645-10. (FPN): For further information, see Protection of Electronic Computer/Data Processing Equipment, NFPA 75-1992 (ANSI). (3) Listed electronic computer/data processing equipment is installed. (FPN): For further information, see Protection of Electronic Computer/Data Processing Equipment, NFPA 75-1992 (ANSI), Section 5-1.1. (4) Occupied only by those personnel needed for the maintenance and functional operation of the installed electronic computer/data processing equipment. 70-672 NATIONAL ELECTRICAL CODE (FPN): The computer room is not to be used for the storage of combustibles beyond that necessary for the day-to-day operation of the equipment. For further information, see Protection of Electronic Computer/Data Processing Equipment, NFPA 75-1992 (ANSI). (5) The room is separated from other occupancies by fire-resistant-rated walls, floors, and ceilings with protected openings. (6) The building construction, rooms, or areas and occupancy comply with the applicable building code. 645-5. Supply Circuits and Interconnecting Cables. (a) Branch Circuit Conductors. The branch circuit conductors supplying one or more units of a data processing system shall have an ampacity not less than 125 percent of the total connected load. (b) Connecting Cables. 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) Computer/data processing cable and attachment plug cap. (2) Flexible cord and an attachment plug cap. (3) Cord-set assembly. Where run on the surface of the floor, they shall be protected against physical damage. (c) Interconnecting Cables. Separate data processing units shall be permitted to be interconnected by means of cables and cable assemblies listed for the purpose. Where run on the surface of the floor, they shall be protected against physical damage. (d) Under Raised Floors. Power cables, communications cables, connecting cables, interconnecting cables, and receptacles associated with the data processing equipment shall be permitted under a raised floor, provided: (1) The raised floor is of suitable construction and the area under the floor is accessible. (FPN): See Protection of Electronic Computer/Data Processing Equipment, NFPA 75-1992 (ANSI). (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, metal wireway, surface metal raceway with metal cover, flexible metal conduit, liquidtight flexible metal or nonmetallic conduit, Type MI cable, Type MC cable, or Type AC cable. These supply conductors shall be installed in accordance with the requirements of Section 300-11. (3) Ventilation in the underfloor area is used for the data processing equipment and data processing area only. (4) Openings in raised floors for cables protect cables against abrasions and minimize the entrance of debris beneath the floor. (5) Cables, other than those covered in (2) above, shall be listed as Type DP cable having adequate fire-resistance characteristics suitable for use under raised floors of a computer room. This listing requirement shall become effective July 1, 1994.