720-Circuits and Equipment Operating
720.1 Scope. This article covers installations operating at less than 50 volts, direct current or alternating current.
720.1 Scope. This article covers installations operating at less than 50 volts, direct current or alternating current.
(A) Number and Size of Conductors in Raceway. Sec- tion 300.17.
727.1 Scope. This article covers the use, installation, and construction specifications of instrumentation tray cable for application to instrumentation and control circuits operating at 150 volts or less and 5 amperes or less.
727.2 Definition.
300.21. The accessible portion of abandoned fire alarm cables shall be removed.
(B) Ducts, Plenums, and Other Air-Handling Spaces. Section 300.22, where installed in ducts or plenums or other spaces used for environmental air.
Exception: As permitted in 760.53(B)(1) and (B)(2) and
760.154(A).
(C) Hazardous (Classified) Locations. Articles 500
770.1 Scope. The provisions of this article apply to the installation of optical fiber cables and raceways. This article does not cover the construction of optical fiber cables and raceways.
770.2 Definitions. See Article 100. For purposes of this article, the following additional definitions apply.
FPN: Rules that are followed by a reference in brackets contain text that has been extracted from NFPA 90A-
2002, Standard for the Installation of Air-Conditioning and Ventilating Systems. Only editorial changes were made to the extracted text to make it consistent with this Code.
under the walk surface within 75 mm (3 in.), bonded to all metal structures and fixed nonelectrical equipment that may become energized, and connected to the electrical grounding system to prevent a difference in voltage from developing within the plane.
810.1 Scope. This article covers antenna systems for radio and television receiving equipment, amateur radio transmitting and receiving equipment, and certain features of transmitter safety. This article covers antennas such as multielement, vertical rod, and dish, and also covers the wiring and cabling that connects them to equipment. This article does not cover equipment and antennas used for coupling carrier current to power line conductors.
685.1 Scope. This article covers integrated electrical systems, other than unit equipment, in which orderly shutdown is necessary to ensure safe operation. An integrated electrical system as used in this article is a unitized segment of an industrial wiring system where all of the following conditions are met:
(1) An orderly shutdown is required to minimize personnel hazard and equipment damage.
FPN: Rules that are followed by a reference in brackets contain text that has been extracted from NFPA 90A-2002, Standard for the Installation of Air- Conditioning and Ventilating Systems. Only editorial changes were made to the extracted text to make it consistent with this Code.
820.1 Scope. This article covers coaxial cable distribution of radio frequency signals typically employed in community antenna television (CATV) systems.