Determining the Spacing Between Cable Tray Hangers

Cable tray hangers should be spaced to support the tray and cables safely, typically ranging from 1. 5 to 3 meters depending on tray type, cable weight, and installation conditions.

General Guidelines

The spacing between cable tray hangers is critical to prevent sagging, maintain structural integrity, and ensure safe cable support. For standard installations: Horizontal runs: Hangers are generally spaced every 1. 5 to 3 meters for ladder or ventilated trays, depending on the tray material, width, and the total weight of the cables supported.

Vertical runs: For vertical risers, hangers or supports should be installed at shorter intervals, often 1 to 1. 5 meters, to prevent stress on the cables and tray. Heavy or densely loaded trays: If the tray carries heavy power cables or large bundles, the spacing should be reduced to maintain stability and prevent excessive deflection.

Factors Affecting Hanger Spacing

Tray Type and Material: Steel trays can span longer distances than aluminum or plastic trays due to higher stiffness. Cable Weight and Size: Heavier cables require closer hanger spacing to avoid sagging and mechanical strain. Environmental Conditions: Outdoor installations or areas with vibration, wind, or seismic activity may require closer hanger spacing.

Deflection Limits: For flexible systems, calculations are often performed to limit tray deflection to 2% of the span to prevent cable displacement.

Practical Recommendations

Rung spacing: For ladder-type trays, rungs are typically spaced 150–230 mm apart to support cables adequately. Parallel trays: Maintain at least 0. 6 meters between trays for maintenance and airflow.

Power vs. signal trays: Keep at least 0. 5 meters apart to reduce electromagnetic interference, or 0. 3 meters if shielded.

Hanger rod diameter: Minimum 8 mm for stability.

Summary

Proper hanger spacing ensures tray stability, prevents cable damage, allows heat dissipation, and facilitates maintenance. Always consider tray type, cable load, environmental factors, and applicable standards (e.g., BS EN 61537, BS 6946) when determining hanger intervals. For precise installations, especially with heavy or flexible cables, engineering calculations should be performed to confirm spacing and deflection limits.