Ladder-type cable trays in Kaiyuan should be installed following approved shop drawings, proper material handling, secure support systems, and compliance with electrical codes to ensure safety and reliability.

Material Preparation and Inspection

All cable trays, ladders, and associated fittings must be inspected upon delivery to ensure they match the approved material submittal and are free from damage or defects. Unsuitable materials should be removed immediately. Trays should be stored horizontally on a flat surface with timber supports at one-meter intervals and protected from moisture and direct sunlight .

Layout Planning

Begin by reviewing the approved shop drawings, which detail the tray routes, lengths, and locations. Mark horizontal and vertical runs on-site, coordinating with other services to avoid clashes. Maintain sufficient clearance for cable pulling and future maintenance . Ladder trays are preferred for single conductor and Type MV cables due to their open design, which allows heat dissipation and secure cable anchoring .

Support Systems

Common support methods include trapeze or swing supports. Vertical hangers should be threaded rods with cross members and washers to allow horizontal adjustment. Ensure the cross member is level and the tray clips are properly attached. Avoid using the ladder tray as a walkway or lifting apparatus .

Installation Procedure

1. Verify civil clearance and clean the installation area.
2. Install hangers and supports according to the layout, ensuring proper spacing and alignment.
3. Position ladder trays on supports, securing with tray clips.
4. Check for level alignment and adjust as necessary.
5. Pull cables into trays, maintaining proper bending radii and avoiding excessive drooping .

Safety and Compliance

All personnel must attend safety induction and demonstrate competency. Follow local building codes, electrical codes, and occupational health and safety procedures. Avoid drilling structural members without approval, and ensure all work is supervised by qualified engineers or site supervisors .

Design Considerations

Select tray widths and rung spacings based on cable type and load. Wider trays and rungs reduce overall strength, so consult manufacturer load charts. For small-diameter control cables, 6–12 inch rung spacing is recommended; for large power cables, 9 inches or wider . By following these steps, ladder-type cable trays in Kaiyuan can be installed safely, efficiently, and in compliance with engineering standards, ensuring long-term reliability for electrical systems.