Should cable trays use cables or wires

Tray-rated cables, not standard individual wires, should be used in cable trays to ensure safety, code compliance, and durability.Recommended ConductorsCable trays are designed to support multi-conductor tray cables (TC) or metal-clad (MC) cables, which are specifically rated for open-air installation and mechanical protection . Standard single wires are generally not suitable because they lack the insulation, jacketing, and structural integrity required for tray environments. Tray cables are manufactured to withstand mechanical stress, exposure to moisture, oil, sunlight, and chemicals, and are UL listed for flammability, temperature, and impact resistance .Types of Tray CablesType TC (Tray Cable): Used for power and control circuits, rated for 600 volts, suitable for industrial and commercial applications, and can be installed in trays, raceways, or outdoor locations with support .TC-ER (Exposed Run): Designed for short exposed runs (up to 6 feet) between the tray and equipment, with crush- and impact-resistant jacketing .ITC (Instrumentation Tray Cable): For low-voltage control, signal, and communication circuits, often shielded to reduce electromagnetic interference .PLTC (Power-Limited Tray Cable): Used for Class 2 and Class 3 circuits, such as alarms, intercoms, and building automation .Installation ConsiderationsNEC Compliance: NEC Article 392 specifies that only tray-rated cables should be used in cable trays, with proper spacing, fill limits, and separation of high- and low-power cables to prevent EMI .Mechanical Support: Cables must be secured at intervals (typically not exceeding six feet for TC-ER) and supported continuously within the tray .Environmental Factors: Choose cable and tray materials based on exposure to corrosive environments, temperature extremes, or outdoor conditions .Key TakeawayAlways use tray-rated cables rather than individual wires in cable trays. This ensures compliance with NEC standards, protects against mechanical and environmental damage, and simplifies maintenance and future upgrades. Selecting the correct type of tray cable depends on voltage, application, environmental conditions, and whether the run is exposed or fully supported within the tray.