Construction sequence of vertical shaft cable trays

The construction of vertical shaft cable trays involves a systematic sequence of material preparation, support installation, alignment, connection, and securing to ensure safe and compliant cable management. 1.

Material Preparation and Inspection

Before installation, all cable trays, ladders, and fittings should be inspected for damage and compliance with approved shop drawings. Materials must be stored horizontally on flat surfaces with timber supports to prevent deformation and protected from moisture and sunlight. Any discrepancies or unsuitable materials should be reported and removed from the site.

2.

Site Planning and Marking

Review approved shop drawings to determine tray layout, lengths, and vertical shaft routing. Mark the locations of supports for vertical and horizontal runs, ensuring coordination with other services to avoid clashes. Identify areas requiring seismic restraints or expansion fittings.

3.

Support Installation

Install threaded rods, Unistrut channels, or other structural supports directly to the building structure or slab surface. Supports should be spaced according to standards, typically not exceeding 1. 2 meters for straight runs.

Ensure supports are aligned vertically and capable of bearing the load of the cable tray and cables. 4.

Tray Assembly and Alignment

Assemble cable trays using approved fittings and connectors, maintaining proper gaps and alignment. For ladder-type trays, ensure rungs are correctly spaced to support cable weight and maintain bending radii. Use spring knots or other fastening methods to secure trays to supports and prevent displacement.

5.

Connection and Securing

Connect tray sections with splice plates or standard fittings, ensuring electrical continuity and proper bonding jumpers. Install expansion joints where required to accommodate thermal movement. Apply protective painting to cut ends and ensure all installed trays are free from damage or scratches.

6.

Final Checks and Compliance

Verify that containment trays are properly aligned, securely fixed, and accessible for cable installation. Ensure retaining bars or insulating devices are installed where cables could fall out. Confirm that all installation complies with relevant standards and safety requirements, including seismic and load considerations.

This sequence ensures that vertical shaft cable trays are structurally sound, safe, and ready for cable installation, while maintaining compliance with engineering and safety standards.