wired between equipment in accordance with the requirements of this Code for the voltage and power delivered:
(1) Storage batteries
(2) Transformers
(3) Transformer rectifiers
(4) Other ac or dc power supplies
FPN: For some equipment, these sources such as in items (1) and (2) serve as the only source of power. These could, in turn, be supplied with intermittent or continuous branch-circuit power.
(E) Between Equipment Racks and Premises Wiring System. Flexible cords and cables shall be permitted for the electrical connection of permanently installed equipment racks to the premises wiring system to facilitate access to equipment or for the purpose of isolating the technical power system of the rack from the premises ground. Connection shall be made either by using approved plugs and receptacles or by direct connection within an approved enclosure. Flexible cords and cables shall not be subjected to physical manipulation or abuse while the rack is in use.
640.22 Wiring of Equipment Racks and Enclosures. Metal equipment racks and enclosures shall be grounded. Bonding shall not be required if the rack is connected to a technical power ground.
Equipment racks shall be wired in a neat and workmanlike manner. Wires, cables, structural components, or other equipment shall not be placed in such a manner as to prevent reasonable access to
equipment power switches and resettable or replaceable circuit overcurrent protection devices.
Supply cords or cables, if used, shall terminate within the equipment rack enclosure in an identified connector assembly. The supply cords or cable (and connector assembly if used) shall have sufficient ampacity to carry the total load connected to the equipment rack and shall be protected by overcurrent devices.
640.23 Conduit or Tubing.
(A) Number of Conductors. The number of conductors permitted in a single conduit or tubing shall not exceed the percentage fill specified in Table 1, Chapter 9.
(B) Nonmetallic Conduit or Tubing and Insulating Bushings. The use of nonmetallic conduit or tubing and insulating bushings shall be permitted where a technical power system is employed and shall comply with applicable articles.
640.24 Wireways, Gutters, and Auxiliary Gutters. The use of metallic and nonmetallic wireways, gutters, and
auxiliary gutters shall be permitted for use with audio
signal conductors and shall comply with applicable
articles with respect to permitted locations,
construction, and fill.
640.25 Loudspeaker Installation in Fire Resistance- Rated Partitions, Walls, and Ceilings. Loudspeakers in stalled in a fire resistance-rated partition, wall, or ceiling shall be listed for that purpose or installed in an enclosure or recess that maintains the fire resistance rating.
FPN: Fire-rated construction is the fire-resistive classification used in building codes. One method of determining fire rating is testing in accordance with NFPA
256-2003, Standard Methods of Fire Tests of Roof Coverings.
III. Portable and Temporary Audio System
Installations
640.41 Multipole Branch-Circuit Cable Connectors.
Multipole branch-circuit cable connectors, male and fe- male, for power-supply cords and cables shall be so constructed that tension on the cord or cable is not transmitted to the connections. The female half shall be attached to the load end of the power supply cord or cable.