Requirements for Spacing of Fire Cable Tray Supports

Fire-rated cable tray supports should typically be spaced between 1.5 and 3 meters for horizontal runs, with vertical runs supported at intervals not exceeding 1.5 meters, using fire-resistant materials.

Horizontal Cable Tray Supports

For horizontal runs, supports should be installed at the start, end, and at every turn of the tray. Along straight sections, supports are generally spaced every 1.5 to 3 meters, depending on the tray type, cable load, and manufacturer recommendations . Additional supports are required near concentrated loads, such as cable entry or exit points, to prevent sagging and mechanical strain . All supports must be fire-resistant, ensuring the cable system remains intact during a fire .

Vertical Cable Tray Supports

For vertical runs, supports should be fixed to the building structure at intervals not exceeding 1.5 meters . Cables within vertical trays should be secured at the top and at every 1.5 meters to maintain stability and prevent undue mechanical stress . Hanging rod supports for vertical trays should be at least 8 mm in diameter to ensure structural integrity .

Fire-Rated and Life-Safety Considerations

Fire-rated cable trays must use supports that will not fail under fire conditions, typically complying with IEC 60331, NFPA, or BS 7671 standards . For life-safety circuits, trays should be dedicated and separated from other circuits, with a recommended 300 mm horizontal air gap if barriers are impractical . This ensures circuit independence and maintains fire integrity.

General Best Practices

• Use metallic or fire-resistant supports; non-metallic clips or ties alone are not sufficient for fire-rated cables .
• Supports should be aligned and level to distribute cable weight evenly.
• Extra supports are recommended at corners, T-junctions, and spans exceeding 30 meters .
• Ensure proper clearance for maintenance, airflow, and heat dissipation to prevent overheating . By following these spacing guidelines and using fire-resistant materials, cable tray systems can maintain structural integrity, comply with safety standards, and ensure reliable operation during fire events.