Installation of Double-Bridge Cable Trays

Double-bridge cable trays should be installed using proper support structures, alignment, and secure fastening to ensure safety, load capacity, and compliance with electrical codes.

Material Preparation and Inspection

Before installation, all cable trays, ladders, and fittings must be inspected for damage and verified against approved material submittals. Any defective or non-compliant materials should be removed from the site immediately. Trays should be stored horizontally on a flat surface with timber supports at 1-meter intervals and protected from moisture and direct sunlight to prevent corrosion or deformation ( ).

Planning and Layout

Review the approved shop drawings to determine the exact layout, length, and location of the double-bridge cable trays. The layout should consider clearances from other services, structural elements, and accessibility for maintenance. The system designer or engineer should ensure that the support structure is adequate for the expected load and complies with local electrical codes ( ).

Support StructuresDouble-bridge cable trays typically require trapeze or swing supports. Install vertical hangers through cross members, ensuring that holes are slightly larger than the threaded rods to allow for adjustment. The cross member should be level and allow for horizontal adjustment of the tray.

Thread hex nuts and square washers to secure the tray, ensuring the tray is level and properly aligned ( ).

Tray Installation

Position the tray on the support structure and attach using tray clips, which can be installed inside or outside the tray depending on space and interference. Ensure adequate spacing between supports to prevent sagging, typically following manufacturer recommendations for double-bridge trays. For horizontal or vertical changes in direction, use fittings such as bends, T-pieces, or cross-overs to maintain structural integrity and cable routing efficiency ( ).

Securing and Alignment

Verify that all vertical hangers are correctly positioned and that the tray is level. Tighten all nuts and bolts while allowing for minor adjustments to maintain alignment. Ensure that the tray system is grounded and bonded according to electrical code requirements to prevent electrical hazards ( ).

Final Checks

Conduct a visual inspection to confirm proper alignment, secure fastening, and absence of damage. Verify that the tray system can support the intended cable load without excessive deflection. Ensure compliance with local electrical codes and safety standards, including spacing, clearances, and grounding ( ).

By following these steps, double-bridge cable trays can be installed safely, efficiently, and in compliance with industry standards, ensuring long-term reliability and ease of maintenance.