Installation diagram of trapezoidal cable tray vertical shaft

Trapezoidal cable trays in vertical shafts should be supported using properly spaced brackets or cantilever supports, ensuring compliance with load requirements, code standards, and safe cable routing.

Planning and Preparation

Before installation, review the approved shop drawings to determine the tray layout, vertical and horizontal runs, and clearances for other services. Inspect all materials for damage and verify that they match the approved specifications. Store trays horizontally on a flat surface with timber supports to prevent deformation and protect from moisture.

Ensure the vertical shaft is clear of obstructions and ready for MEP installations.

Support Methods

For vertical shafts, cantilever wall brackets or trapeze hangers are commonly used. Cantilever brackets are mounted directly to the shaft walls and provide rigid support for vertical runs. Trapeze hangers can be used when multiple trays or services need to be supported together.

The choice depends on the shaft structure and the number of trays.

Support Spacing

The distance between supports must be calculated based on the tray manufacturer's load capacity and the total anticipated weight of cables. Overloading or excessive spacing can lead to tray deformation or failure. Typically, vertical supports are placed at intervals that maintain structural integrity while allowing for cable installation and future maintenance.

Installation Steps

Mark the tray route on the shaft walls according to the approved drawings, ensuring vertical alignment and clearance for cable pulling. Install support brackets securely to the shaft walls using appropriate anchors or fasteners, considering the shaft material and load requirements. Mount the trapezoidal cable trays onto the supports, ensuring they are level and aligned vertically.

Use connectors and fittings to join tray sections securely. Check clearances for other services and maintain sufficient space for cable pulling and future maintenance. Secure the trays with bolts, clamps, or locking mechanisms as specified by the manufacturer to prevent movement during cable installation.

Material Considerations

Trapezoidal trays are typically made from steel, stainless steel, or aluminum, with finishes selected based on environmental conditions. In vertical shafts, corrosion resistance and mechanical strength are critical, especially in humid or industrial environments.

Compliance and Safety

Ensure all installation work complies with the National Electrical Code (NEC) Article 392, local building codes, and occupational health and safety regulations. Proper planning, support selection, and adherence to load ratings are essential to maintain both electrical and structural safety. By following these guidelines, trapezoidal cable trays can be safely and efficiently installed in vertical shafts, providing reliable support for electrical cables and facilitating future maintenance and upgrades.