Resolución 2535: adopta el Código Eléctrico Nacional, versión 1993. (Sustituye el Anejo A del Reglamento 4435)

351-9. Grounding. Liquidtight flexible metal conduit shall be permitted as a grounding conductor where both the conduit and the fittings are approved for grounding. Where an equipment bonding jumper is required around liquidtight flexible metal conduit, it shall be installed in accordance with Section 250-79. Exception No. 1: Where used to connect equipment and flexibility is required, an equipment grounding conductor shall be installed. Exception No. 2: Listed liquidtight flexible metal conduit shall be permitted as a grounding means in the 11/4-inch and smaller trade sizes if the total length of all liquidtight flexible metal conduit in any ground return path is 6 feet (1.83 m) or less, the conduit is terminated in fittings listed for grounding, and the circuit conductors contained therein are protected by overcurrent devices rated at 20 amperes or less for ³/₈-inch and ¹/₂-inch trade sizes and 60 amperes or less for ³/₄-inch through 11/4-inch trade sizes. (FPN): See Sections 501-16(b), 502-16(b), and 503-16(b) for types of equipment grounding conductors. 351-10. Bends - Number in One Run. There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, e.g., conduit bodies and boxes. 351-11. Splices and Taps. Splices and taps shall be made only in junction boxes, outlet boxes, device boxes, or conduit bodies. See Article 370. B. Liquidtight Flexible Nonmetallic Conduit 351-22. Definition. Liquidtight flexible nonmetallic conduit is a raceway of circular cross section of various types: (1) A smooth seamless inner core and cover bonded together and having one or more reinforcement layers between the core and cover. (2) A smooth inner surface with integral reinforcement within the conduit wall. (3) A corrugated internal and external surface without integral reinforcement within the conduit wall. This conduit is flame-resistant and, with fittings, is approved for the installation of electrical conductors. 351-23. Use. (a) Permitted. Liquidtight flexible nonmetallic conduit shall be permitted to be used in exposed or concealed locations: (FPN): Extreme cold may cause some types of nonmetallic conduits to become brittle and therefore more susceptible to damage from physical contact. (1) Where flexibility is required for installation, operation, or maintenance;