Spacing of cable tray fixed hangers

Cable tray fixing hangers should generally be spaced 1 to 1.5 meters apart for horizontal runs and up to 2 meters for vertical runs, with closer spacing at bends, junctions, and heavy loads.

Horizontal Runs

For straight horizontal cable tray sections, hangers or brackets are typically installed at intervals of 1 to 1.5 meters to prevent sagging and maintain structural integrity. Cables should also be secured at the start, end, and at bends of the tray to avoid undue mechanical strain on the conductors ( ). For flexible systems, calculations may be required to determine hanger spacing based on cable stiffness and allowable deflection ( ).

Vertical Runs

Vertical cable tray runs require supports fixed to the building structure at intervals preferably less than 2 meters. Cables should be secured at the top and every 1.5 meters along the vertical section to maintain stability and prevent displacement ( ).

Bends, Junctions, and Special Points

At corners, T-junctions, or changes in direction, one hanger should be installed on each side of the bend, arranged symmetrically. This ensures the tray remains stable and the cables are not exposed to stress ( ). For long vertical runs exceeding 32 meters, strain relief sections should be incorporated, typically offset by at least two cable diameters to accommodate expansion ( ).

Load and Material Considerations

The spacing of hangers also depends on the weight of the cables, the tray material, and environmental factors such as vibration or temperature fluctuations. Heavier loads or harsher conditions may require closer hanger spacing to maintain safety and prevent sagging ( ). Tray manufacturers often provide load capacity guidelines to inform optimal bracket spacing.

Regulatory and Best Practice Notes

• All cable supports should be fire-resistant to prevent premature failure in case of fire ( ).
• Horizontal spacing between power and signal trays should generally be at least 0.5 meters, or 0.3 meters if shielded, to reduce electromagnetic interference ( ).
• Fixed supports are critical at the beginning and end of trays, at corners, T-junctions, and spans over 30 meters ( ). By following these guidelines, cable tray systems can maintain structural integrity, ensure safety, and allow for proper maintenance, ventilation, and heat dissipation.