Calculation of Vertical Installation Brackets for Cable Trays

Vertical installation brackets for cable trays must be calculated based on tray type, cable load, span length, and applicable standards to ensure safe and stable support.

Key Considerations

1. Determine the Load Requirements The first step is to calculate the total load the vertical brackets must support. This includes:

• Cable weight: Sum of all cables in the tray per unit length.
• Tray weight: The weight of the cable tray itself.
• Additional loads: Environmental factors such as wind, ice, or seismic forces if applicable . 2. Identify Tray Type and Material Different cable trays (ladder, solid-bottom, or mesh) have varying load capacities. Steel and stainless steel trays are common, with galvanization or coatings for corrosion protection . The material affects the allowable span between supports. 3. Determine Vertical Bracket Spacing Vertical brackets are used to support cable trays on walls or structural columns. The spacing depends on:
• Tray type and width: Wider trays require closer support.
• Load per unit length: Heavier cable loads reduce allowable span.
• Manufacturer recommendations: Always follow the tray manufacturer's specifications for maximum span . Typical vertical bracket spacing ranges from 1.5 m to 3 m for standard ladder or solid trays, but this can vary based on load and tray type. 4. Calculate Bracket Strength Brackets must be designed to withstand:
• Static load: Weight of tray and cables.
• Dynamic load: Forces from installation, maintenance, or short-circuit events.
• Safety factor: Usually 1.5 to 2 times the calculated load to ensure compliance with standards . 5. Installation Guidelines
• Brackets should be securely anchored to structural elements (walls, columns, or beams).
• Ensure vertical alignment to prevent tray sagging.
• Use compatible fasteners and hardware as recommended by the tray manufacturer .
• For long vertical runs, intermediate brackets may be required to prevent deflection. 6. Compliance with Standards
• Follow DIN EN 61537 or BS EN 61537 for cable tray support systems.
• Ensure brackets and trays are tested together as a system to maintain safety and mechanical integrity .

Practical Example

For a steel ladder tray carrying 50 kg/m of cables with a tray weight of 10 kg/m, and a maximum allowable deflection of L/200:

1. Total load per meter = 50 + 10 = 60 kg/m.
2. Using manufacturer tables, a 2 m span may be allowed for this load.
3. Vertical brackets should be installed every 2 m along the wall or support structure.
4. Brackets must be rated for at least 90–120 kg per support (including safety factor). By following these steps, vertical installation brackets can be properly calculated to ensure structural stability, compliance, and safe cable management .