Cable tray fixing points should generally be spaced every 3–5 meters for horizontal runs and every 1.5–2 meters for vertical runs, with adjustments based on cable weight, type, and system design.

Horizontal Cable Tray Runs

For straight horizontal sections, supports or fixings should be installed at the start, end, and at every 3 to 5 meters along the tray. Additional supports are required at corners, T-junctions, and where the tray spans more than 30 meters to prevent sagging and maintain structural integrity. Proper horizontal spacing ensures stability, reduces stress on cables, and allows for maintenance and inspection access .

Vertical Cable Tray Runs

For vertical runs, supports should be fixed to the building structure at intervals preferably less than 2 meters, with cables secured at the top and every 1.5 meters. Long vertical runs exceeding 32 meters may require strain relief sections, often implemented by offsetting the cable horizontally by at least 2 cable diameters or including a short horizontal section of at least 1 meter to prevent excessive tension .

Special Considerations

• Cable type and weight: Heavier or stiffer cables, such as MDPE sheathed cables, require shorter spacing between supports to limit deflection or sag, while lighter cables like LSOH may allow longer spacing .
• Bends and junctions: Supports should be placed on either side of bends to maintain the minimum bending radius and prevent mechanical strain .
• Environmental factors: Supports must withstand mechanical loads, weather, and ambient conditions, and fire-resistant supports are recommended for all cable types .
• Binding and organization: Cables within trays should be laid straight, tied at intervals not exceeding 1.5 meters, and properly secured to avoid crossing or protrusion .

Summary

• Horizontal runs: every 3–5 meters, plus start, end, and bends.
• Vertical runs: every 1.5–2 meters, with strain relief for long runs.
• Corners, T-junctions, and spans >30 m: additional supports required.
• Adjust spacing based on cable weight, stiffness, and environmental conditions. Following these guidelines ensures structural stability, cable safety, and compliance with standards such as BS EN 61537 and DIN EN 61537 .