Due to their exposure to the open air because of the cable trays, the wires contained within need a very durable outer covering. The regulations dictate that the cables must either be Type TC (also known as Tray Rated) or must be metal-armored (Type MC). The short answer is no. Cable tray types, fill rules for single-conductor and multiconductor cables, ampacity derating, separation requirements, and when to use tray vs conduit. When properly selected and installed, cable trays simplify routing, improve accessibility, and support future expansion while. Size conductors installed in cable tray with NEC 392, NEC 310. Use NEC 392 for tray rules, but still size conductors from NEC 310. Tray fill, spacing, ambient temperature, and sun exposure. AFTER FIREPROOFING AND INSULATION IS INSTALLED 4. NOMINAL MINIMUM SEPARATION BETWEEN CONDUITS OF REDUNDANT ELASS IE DIVISIONS IS C INCHES LE MANI ERRATE REDUCED TO | INCH FOR CONDUITS ROUTED THROUGH WALL AND FLOOR PENETRATIONS, AND ON CONCLIIT RUNS WHERE THE SEISMIC ATTACHMENT CRITERIA, AS SHOWN. NEC Article 392 governs cable tray systems. Firestop systems are required at penetrations.