FIXED OUTDOOR ELECTRIC DEICING

AND SNOW-MELTING EQUIPMENT A. General 426-1. Scope. The requirements of this article shall apply to electrically energized heating systems and the installation of these systems. (a) Embedded. Embedded in driveways, walks, steps, and other areas. (b) Exposed. Exposed on drainage systems, bridge structures, roofs, and other structures. 426-2. Definitions. For the purpose of this article: Heating System. A complete system consisting of components such as heating elements, fastening devices, nonheating circuit wiring, leads, temperature controllers, safety signs, junction boxes, raceways, and fittings. Resistance Heating Element. A specific separate element to generate heat that is embedded in or fastened to the surface to be heated. (FPN): Tubular heaters, strip heaters, heating cable, heating tape, and heating panels are examples of resistance heaters. Impedance Heating System. A system in which heat is generated in a pipe or rod, or combination of pipes and rods, by causing current to flow through the pipe or rod by direct connection to an ac voltage source from a dual-winding transformer. The pipe or rod shall be permitted to be embedded in the surface to be heated, or constitute the exposed components to be heated. Skin Effect Heating System. A system in which heat is generated on the inner surface of a ferromagnetic envelope embedded in or fastened to the surface to be heated. (FPN): Typically, an electrically insulated conductor is routed through and connected to the envelope at the other end. The envelope and the electrically insulated conductor are connected to an ac voltage source from a dual-winding transformer. 426-3. Application of Other Articles. All requirements of this Code shall apply except as specifically amended in this article. Cord- and plugconnected fixed outdoor electric deicing and snow-melting equipment intended for specific use and identified as suitable for this use shall be installed according to Article 422. Fixed outdoor electric deicing and snowmelting equipment for use in hazardous (classified) locations shall comply with Articles 500 through 516. 426-4. Branch-Circuit Sizing. The ampacity of branch-circuit conductors and the rating or setting of overcurrent protective devices supplying fixed outdoor electric deicing and snow-melting equipment shall not be less than 125 percent of the total load of the heaters. The rating or setting of overcurrent protective devices shall be permitted in accordance with Section 240-3(b).