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. 16, tray fill, ampacity adjustment, voltage-drop checks, grounding, and IEC design cross-checks. Use NEC 392 for tray rules, but still size conductors from NEC 310. Tray fill, spacing, ambient temperature, and sun exposure. Cable tray systems provide a safe, organized, and flexible method for supporting insulated conductors and cables in commercial and industrial electrical installations. When properly selected and installed, cable trays simplify routing, improve accessibility, and support future expansion while. The primary rulebook used in the safe use of cable trays is NEC Article 392.