Requirements for Ladder Installation in Cable Trays

Ladder cable trays must be installed according to standards, with proper support spacing, load capacity, and handling procedures to ensure safety and functionality.

Standards and Compliance

Ladder cable trays should be manufactured and installed in accordance with BS EN 61537 for cable tray systems and BS 6946 for channel support systems . Installation should be performed by competent personnel familiar with electrical installation practices and safety requirements . These systems are designed to support cables, not as walkways or ladders for personnel, to prevent injury and damage .

Support and Load Requirements

• Support Spacing: Maximum support spacing is typically 3.6 meters for center-hung or trapeze supports .
• Load Capacity: Each hanger can support 318–340 kg (700–750 lbs) depending on the system .
• Cross Members: Vertical hangers pass through cross members, which should have holes 1/16" to 1/8" larger than the all-thread diameter to allow adjustment without thread damage .
• Deflection Limits: Ensure that tray deflection does not exceed manufacturer-specified limits to maintain structural integrity .

Material Handling and Storage

• Offloading: Use cranes or forklifts carefully; do not attach slings or chains directly to the tray to avoid crushing or damage .
• Storage: Store trays horizontally on flat surfaces with timber supports at 1-meter intervals, and protect from moisture and direct sunlight .
• Stacking: Stack trays by width and type; outdoor storage is acceptable for most trays if covered and ventilated, except for PVC or painted trays .

Installation Procedure

1. Review Shop Drawings: Confirm tray layout, lengths, and locations according to approved drawings .
2. Prepare Materials: Verify all trays, ladders, and fittings for damage and compliance with specifications before installation .
3. Install Supports: Use trapeze or swing supports, ensuring cross members are level and properly adjusted .
4. Attach Tray Clips: Install tray clips inside or outside the tray as allowed, ensuring proper alignment and horizontal adjustment .
5. Cable Placement: Center-hung supports allow cables to be deposited from both sides, facilitating installation .

Environmental and Material Considerations

• Material Selection: Choose tray materials (steel, aluminum, stainless steel) based on environmental conditions, corrosion resistance, and mechanical strength .
• Ventilation: Ensure adequate airflow for ventilated trays to prevent heat buildup, especially for instrumentation and control cables .
• Covers: Solid covers may be used where additional protection or aesthetics are required . Following these guidelines ensures safe, durable, and compliant installation of ladder cable trays, supporting both current and future cable loads while minimizing risk of damage or failure.