Should the light wiring be run through cable trays

Yes, lighting wires can be run through cable trays if they comply with NEC requirements, are properly rated, and are installed with appropriate separation from other circuits.NEC Compliance and Cable Types

Cable trays are designed to support electrical conductors, including service conductors, feeders, branch circuits, and lighting circuits (NEC Article 392.3) . However, not all cables are suitable for tray installation. Wires must be tray-rated (Type TC) or metal-armored (Type MC) to withstand exposure to air and potential mechanical stress . Standard non-rated building wiring is generally not permitted in open cable trays.

Voltage and Separation Requirements

Lighting circuits typically operate at 120 volts or less, which can be installed in the same tray with other low-voltage circuits if they meet NEC fill and support requirements . For circuits above 600 volts, cables must either be Type MC or separated by a solid barrier from lower-voltage cables to prevent electrical interference . Additionally, a minimum separation of two inches is recommended between power and communication or control cables to reduce noise and interference .

Tray Types and Installation Considerations

• Ladder-type trays are preferred for lighting and power circuits because they allow air circulation, which helps dissipate heat from multiple cables .
• Solid-bottom trays may be used where aesthetics or electromagnetic interference (EMI) is a concern .
• Cables must be secured at intervals according to manufacturer instructions, and the tray should not exceed the maximum fill capacity specified by the NEC .

Practical Tips

• Ensure the tray is accessible for maintenance and inspection.
• Use covers in high-traffic areas or outdoor installations to protect cables from physical damage and UV exposure .
• Avoid running non-electrical piping or tubing in the same tray as lighting wires, as this is prohibited by NEC Section 300-8 . By following these guidelines, lighting wires can be safely and effectively routed through cable trays in compliance with NEC standards.