For horizontal cable tray runs, hangers or supports should typically be spaced between 1.5 meters and 3 meters, with closer spacing at bends, junctions, or heavy cable loads to ensure stability and prevent sagging.

General Guidelines for Horizontal Cable Tray Supports

• Straight Horizontal Runs: Supports should generally be installed every 1.5 to 3 meters along the tray, depending on the tray type, material, and cable load. This spacing ensures the tray remains stable and prevents excessive sagging of cables ( ).
• Bends and Corners: At corners or bends, it is recommended to place one hanger on each side of the bend, arranged symmetrically, to maintain tray stability and prevent mechanical stress on the cables ( ).
• Start and End Points: Supports must be installed at the beginning and end of each tray section, as well as at T-junctions or where the tray spans more than 30 meters ( ).
• Cable Securing: Cables should be secured at the start, end, and turns, and along straight sections every 3 to 5 meters, depending on cable type and weight ( ).

Considerations for Load and Material

• Tray Type: Ladder trays, perforated trays, and wire mesh trays have different load capacities. Heavier cables or ladder trays may require closer support spacing ( ).
• Hanger Material: Hanging rods should be at least 8 mm in diameter to provide adequate support for vertical and horizontal runs ( ).
• Flexible Systems: For systems like J-hanger installations, calculations may be needed to determine spacing based on allowable deflection, typically including a 2% initial offset ( ).

Compliance and Safety

• Standards: Supports should comply with BS 7671 and NEC guidelines, ensuring cables are not exposed to undue mechanical strain and that fire-resistant supports are used where required ( ).
• Fire Safety: All cable supports must be made of materials that will not fail in a fire, and wiring systems should be supported to prevent collapse during fire conditions ( ).

Summary

For most horizontal cable tray installations:

• Support spacing: 1.5–3 meters for straight runs
• Bends/corners: One hanger on each side
• Start/end of tray: Always supported
• Heavy loads or long spans: Reduce spacing and consider additional supports
• Cable securing: Every 3–5 meters along straight sections Following these guidelines ensures structural integrity, safety, and compliance while minimizing cable sag, mechanical strain, and potential interference.