Article 392 of the NEC provides the basic requirements for installations using cable tray. The respective article for the cable type must also be followed. 10 (see Table 1) lists the type of cable that is allowed to be installed in tray and the types of. Cable tray types, fill rules for single-conductor and multiconductor cables, ampacity derating, separation requirements, and when to use tray vs conduit. These systems, made from metal or plastic, are open structures designed to support electrical conductors, ensuring proper organization and safety. These rules have to be respected scrupulously by the engineering. maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray. 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.