Yes, cables can be laid in cable trays, but only if they are tray-rated and installed according to NEC standards and proper installation practices.

Types of Cables Permitted

Cable trays are designed to support a variety of cables, including power cables, control cables, Ethernet, and fiber optic cables. However, only approved tray-rated cables should be installed to ensure safety and compliance with the National Electrical Code (NEC) Article 392 . Tray-rated cables are specifically designed to withstand heat, moisture, and physical stress commonly encountered in tray installations .

Tray Types and Installation Considerations

• Ladder Trays: Open design with side rails and rungs, providing excellent ventilation. Ideal for heavy power cables and industrial applications. Cables can be installed in single layers or grouped circuits, maintaining spacing for ampacity purposes .
• Solid-Bottom Trays: Enclosed design, used where visual aesthetics or EMI protection is required. Heat buildup is higher, so fewer cables should be installed compared to ladder trays .
• Channel or Wire-Mesh Trays: Used for light instrumentation and control cables, offering flexibility and protection against electromagnetic interference .

Installation Guidelines

• Circuit Grouping: Single-conductor cables must be installed in circuit groups to prevent inductive heating .
• Fill Limits: Tray fill must be calculated based on cable size, type, and tray dimensions to avoid overheating and maintain accessibility for maintenance .
• Bend Radius and Tension: Cables must respect minimum bend radius and maximum pulling tension to prevent damage during installation .
• Grounding and Bonding: Metallic trays must be electrically continuous and properly bonded to the building grounding system to ensure safety .
• Segregation: Power and signal cables may require separation to reduce interference and maintain performance .

Practical Benefits

Using cable trays allows for organized, scalable, and accessible cable management, especially in industrial facilities, data centers, and large commercial buildings. They simplify maintenance, reduce installation costs compared to individual conduits, and support high-density cable routing .

In summary, cables can be safely installed in cable trays if they are tray-rated, properly grouped, spaced, and installed according to NEC guidelines and best practices for grounding, fill, and mechanical protection.