Methods for Laying Lighting Cables in Cable Trays

Yes, lighting cables can be run through cable trays if they are rated for tray use and installed according to NEC requirements.

Cable Types and Ratings

Lighting circuits can be installed in cable trays using Tray Cable (TC) or Metal-Clad (MC) cables that are specifically rated for open-air environments and tray installations . For residential or exposed runs, TC-ER-JP cables are approved for lighting and power circuits without conduit, provided all support and protection requirements are met . Standard TC cables are generally not permitted in dwelling units unless they meet the specific NEC designation.

Installation Guidelines

• Tray Fill Limits: For power, lighting, or signal cables, the total cross-sectional area of all cables must not exceed 40% of the tray's cross-sectional area to prevent overheating .
• Separation: High-power and low-power circuits, including lighting and control cables, should be separated to reduce electromagnetic interference (EMI), .
• Clearances: Maintain at least 12 inches of vertical clearance above trays for installation and maintenance access .
• Tray Types: Ladder trays are preferred for power and lighting circuits because their open design allows better ventilation and heat dissipation, while ventilated troughs or solid-bottom trays may be used for smaller or protected cables .

Safety and Compliance

• Grounding: Metallic trays can serve as an Equipment Grounding Conductor (EGC) if properly bonded and electrically continuous .
• Accessibility: Cable trays must remain accessible and cannot be installed in hoistways or fully enclosed spaces .
• Environmental Considerations: For corrosive or high-moisture environments, fiberglass-reinforced plastic (FRP) trays provide corrosion resistance and non-conductive protection .

Practical Considerations

Using cable trays for lighting circuits simplifies routing, allows for future expansion, and provides mechanical protection. However, careful planning is required to avoid overfilling, overheating, or interference with other circuits. Always verify local code amendments and NEC compliance before installation . In summary, lighting cables can safely and legally be run through cable trays as long as the cables are tray-rated, fill limits are observed, proper separation is maintained, and all NEC installation requirements are followed.