MI, mineral insulated cable, with termination fittings approved for the location, has been permitted in Class I, Division 1 and Class II, Division 1 locations since the 1962 NEC. This cable can be installed in cable trays in Division 1 locations and can also provide fire. Cable Trays have been permitted in the hazardous (classified) locations in the National Electrical Code for Class I (flammable vapor and gases) since the 1978 NEC and have been used extensively in chemical plants, refineries, and other types of facilities. As a cable tray supplier, I've had numerous discussions with mining operators, engineers, and safety experts about the feasibility and practicality of using cable trays in such a. NEC Article 392 explains cable trays, their components, appropriate wiring methods for cable trays, and instances where they are and are not permitted for use. It also focuses on construction and installation practices for cable trays. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when the cable tray cont d for instrumentation and control applications that require. cable trays are equivalent. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned in this technical guide only apply to our own cable management ranges and cannot under any circumstances be transposed to si osure, overheating or.