How to run cable trays through cable wells

Cable trays in cable wells are installed by planning the route, selecting the appropriate tray type, mounting supports, securing the trays, and properly laying and fastening cables according to standards.

Planning and Preparation

Before installation, review approved shop drawings to determine the tray layout, length, and location within the cable well, ensuring proper clearance and load capacity for the cables to be supported. Inspect all materials for damage and verify that they meet project specifications. Store trays horizontally on a flat surface with timber supports to prevent deformation or moisture damage.

Selecting Tray Type and Size

Choose the appropriate tray type based on cable type, load, and environmental conditions. Common types include ladder trays for large power cables, ventilated troughs for smaller control cables, and solid-bottom trays for protection against dust or electromagnetic interference. Calculate tray width and depth according to the number and size of cables to prevent overcrowding and overheating.

Mounting Supports

Install supports and hangers at regular intervals, typically 1. 5 to 3. 6 meters apart, depending on tray type and load.

In cable wells, center-hung supports are often used to allow cables to be deposited from both sides, facilitating easier installation. Ensure that supports are level and securely anchored to the well walls or structural elements.

Installing the Trays

Position the trays on the supports and secure them using brackets, clamps, or bolts. Maintain proper alignment and spacing to allow for cable bending and future maintenance. For ladder trays, ensure rungs are spaced 150–230 mm apart to support cables without sagging.

Check that the minimum bend radius of cables is maintained at tray entry and exit points.

Laying and Securing Cables

Once trays are installed, lay cables neatly, keeping them separated according to type and voltage to prevent interference. Use cable ties or clamps to secure cables to the tray rungs or bottom, avoiding over-tightening that could damage insulation. Ensure grounding and bonding of metallic trays according to NEC Article 392 or relevant local codes.

Final Checks

Perform a visual inspection to confirm proper alignment, secure fastening, and compliance with design specifications. Verify that all cables are supported, bend radii are respected, and there is no damage to insulation or tray components. Label trays and cables as required for maintenance and future upgrades.

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