Fixing of outdoor overhead cable trays

Outdoor overhead cable trays should be securely mounted using appropriate support brackets, hangers, and corrosion-resistant materials, with proper spacing to handle mechanical loads and environmental conditions.

Material and Environmental Considerations

For outdoor installations, steel or stainless steel trays are recommended, often with galvanization or protective coatings to resist corrosion from rain, UV exposure, and other environmental factors ( ). PVC-coated or painted trays can also be used, but proper ventilation and drainage must be ensured to prevent moisture accumulation ( ).

Support and Mounting

Cable trays must be supported using wall brackets, suspended supports, or center-hung hangers. Maximum support spacing typically ranges from 3 to 3.6 meters, depending on tray size and load ( ). Each hanger should be rated for the maximum load, often between 318 kg to 340 kg for standard trays ( ). For T-joints or bends, additional support brackets should be installed to maintain alignment and prevent sagging ( ).

Installation Steps

1. Plan the route: Ensure the tray path avoids obstacles and allows for future maintenance ( ).
2. Mark and drill supports: Use scribing or metal marking tools to position hangers accurately. Obtain approval before drilling structural members ( ).
3. Install hangers and brackets: Securely attach supports to walls, ceilings, or steel structures using bolts, nuts, or all-thread rods. Center-hung supports allow easier cable placement ( ).
4. Mount tray sections: Lift and place straight sections onto supports, ensuring proper alignment. For T-joints or bends, use dedicated fittings and clamps ( ).
5. Secure cables: Use cable organizers, dividers, clamps, and spacers to prevent tangling, maintain airflow, and reduce electromagnetic interference ( ).

Safety and Compliance

• Cable trays are mechanical supports for cables only and should not be used as walkways or lifting points ( ).
• Ensure compliance with BS EN 61537 or equivalent standards for cable support systems ( ).
• Avoid overloading trays and maintain proper separation between power and signal cables to prevent overheating and short circuits ( ).

Maintenance Tips

• Inspect trays periodically for corrosion, sagging, or loose fittings.
• Ensure drainage holes are clear to prevent water accumulation.
• Replace damaged sections or accessories promptly to maintain system integrity. By following these guidelines, outdoor overhead cable trays can be installed safely, remain structurally sound, and provide reliable cable management for years ( ).