How to construct a trapezoidal cable tray shaft

Constructing a trapezoidal cable tray shaft involves careful planning, proper material selection, precise fabrication, and secure installation to support cables safely and efficiently.

Planning and Design

Determine the load requirements: Calculate the total weight of cables, including future expansion, and any imposed loads such as wind or seismic forces. Ensure the shaft can withstand short-circuit forces if carrying power cables (BS 6946 guidance). Define dimensions: The trapezoidal shape should allow adequate cable spacing and bending radius.

Typically, the wider base supports heavier cable loads, while the narrower top reduces material usage and allows easier access. Select materials: Common materials include galvanized steel, aluminum, or fiber-reinforced plastic, chosen based on environmental conditions, corrosion resistance, and mechanical strength.

Fabrication

Cut and shape panels: Fabricate the trapezoidal sections according to the approved shop drawings. Ensure edges are smooth to prevent cable damage. Drill mounting holes: Pre-drill holes for bolts, supports, and accessories to facilitate assembly and alignment.

Assemble sections: Use high-tensile bolts, washers, and nuts to join sections. Ensure the trapezoidal geometry is maintained and the structure is rigid.

Installation

Prepare the site: Ensure the shaft location is clear, level, and free from obstructions. Store materials in a dry, covered area to prevent corrosion. Install supports: Mount brackets or hangers at intervals recommended by the manufacturer or standards (typically 1.

5–3 meters for heavy loads). Supports must be aligned to maintain the trapezoidal shape. Position the tray sections: Lift and secure each trapezoidal section onto the supports.

Use levels to ensure proper alignment and slope for drainage if required. Secure cables: Lay cables carefully, maintaining minimum bend radius and spacing. Use cable ties or clamps to prevent movement and stress on the cables.

Install covers if needed: For protection against dust, moisture, or electromagnetic interference, install solid or ventilated covers according to the design.

Safety and Compliance

Follow BS E

N 61537 for cable tray manufacturing and installation standards. Ensure all personnel are trained and competent in electrical installation practices. Avoid using the tray as a walkway or support for personnel to prevent injury and structural damage.

Inspect all connections and supports for tightness and alignment before energizing the system. By following these steps, a trapezoidal cable tray shaft can be constructed to provide safe, durable, and efficient cable management for electrical and communication systems.