Wire for cable trays

Cable tray wiring requires UL-listed, tray-rated cables designed for safe support, routing, and protection of power, control, and communication circuits.

Types of Cables for Cable Trays

Cable trays are used to support and organize electrical wiring in industrial, commercial, and institutional installations. The most commonly used cables include: Tray Cable (TC): Factory-assembled cables with two or more insulated conductors, optionally including grounding conductors, under a non-metallic jacket. Rated for 600 volts, TC cables are suitable for power and control circuits and are often flame-retardant ( ).

Metal-

Clad (MC) Cable: Provides additional mechanical protection with a metallic armor, suitable for 600-volt motor power and control applications ( ). Instrumentation and Control Cables: Smaller gauge cables for signal and control circuits, often requiring additional protection in trays with solid or ventilated bottoms ( ).

Exposure-

Rated (ER) Cables: Designed for outdoor or harsh environments, capable of withstanding UV, moisture, and temperature extremes ( ).

Installation Considerations

Support and Securing: Cables must be properly supported within the tray and secured at intervals to prevent sagging or movement ( ). Bend Radius: Maintain the minimum bend radius for cables as they exit the tray to avoid damage ( ). Fill Capacity: Ensure the tray is not overfilled to maintain proper heat dissipation and prevent overheating ( ).

Separation of Circuits: Power, control, and communication cables may require separation to reduce electromagnetic interference ( ).

Material and Environmental Suitability

Cable trays can be made from steel, stainless steel, aluminum, or PVC, and the choice of cable should match the environmental conditions: Indoor, dry environments: Standard TC or MC cables are sufficient ( ). Corrosive or outdoor environments: Use ER cables or cables with UV-resistant jackets, and consider stainless steel or PVC trays for added protection ( ). High-temperature areas: Select cables rated for elevated temperatures to prevent insulation degradation ( ).

Compliance and Standards

All cables used in cable trays should be UL-listed and marked as tray-rated, ensuring compliance with the National Electrical Code (NEC) Section 392. 10 and related articles. This guarantees that the cables meet requirements for flammability, mechanical resistance, and temperature limitations ( ).

By selecting the appropriate cable type, rating, and installation method, cable trays provide a safe, organized, and flexible solution for routing electrical and communication wiring in a wide range of applications.