Cable tray clip position

Cable tray clips should be positioned to support cables at regular intervals, near bends, and at strain relief points to prevent sagging, stress, or displacement.

General Guidelines for Clip Placement

• Spacing Between Clips: The distance between cable tray clips depends on the cable diameter and type. For small cables (up to 9 mm diameter), clips are typically spaced closer together, while larger cables can have greater spacing. The IET On-Site Guide and BS 7671 provide recommended distances to ensure cables are not under undue strain .
• Near Bends: Clips should be installed on either side of bends in the cable tray to maintain the cable's shape and prevent excessive stress at the curve .
• Vertical Runs: For long vertical cable runs, strain relief sections should be incorporated. This can involve offsetting the cable by at least two cable diameters or including short horizontal sections (at least 1 meter) to relieve tension .
• Horizontal Runs: Clips should maintain the cable in a stable horizontal plane, preventing sagging or displacement. For flexible systems, a small initial offset (around 2%) is recommended to accommodate thermal expansion .

Practical Considerations

• Material of Clips: Use fire-resistant and mechanically robust clips, especially for fire-rated or critical installations, to prevent premature failure .
• Cable Type: Different cables (power, instrumentation, control) may require specific clip types or additional protection, such as solid or ventilated tray bottoms for heat dissipation .
• Support at Junctions and Fittings: Clips should also be positioned near T-pieces, crossovers, reductions, or end closures to maintain cable alignment and prevent stress at these points .

Summary

Proper clip positioning ensures mechanical support, strain relief, and compliance with safety standards. Key points include:

• Place clips at regular intervals according to cable diameter.
• Support cables on both sides of bends.
• Include strain relief for long vertical runs.
• Use fire-resistant, durable clips suitable for the cable type.
• Ensure clips maintain cable alignment at junctions and fittings. Following these guidelines will help maintain cable integrity, prevent sagging or displacement, and ensure compliance with BS 7671 and IET recommendations .