How to connect cable trays at corners

Cable trays at corners are installed using pre-fabricated elbows or custom bends, ensuring proper support, minimum bend radius, and grounding continuity.

Use of Elbows and Bends

At corners, pre-fabricated 90° or 45° elbows are commonly used to maintain the cable tray path without sharp bends that could damage cables or exceed the minimum bend radius of the largest cable in the tray. For non-standard angles, custom bends can be fabricated, ensuring the radius is sufficient to prevent cable stress.

Support and Fixing

Supports should be installed within 300 mm of joints or elbows to maintain stability and prevent sagging. Vertical and horizontal trays must be aligned with building features and fixed using appropriate bolts and channels according to load requirements. For hollow block walls, expansion bolts and C-channels are used to secure the tray at corners.

Grounding and Continuity

Earth continuity strips should be installed at all joints and elbows to maintain electrical grounding. A separate grounding cable may be connected to the earth bar for additional safety.

Installation Steps

Review approved shop drawings to identify corner locations and required elbow types. Inspect materials for damage and verify dimensions before installation. Mark the corner locations on the wall or ceiling and install support channels or brackets.

Attach the elbow or bend to the straight tray sections, ensuring proper alignment and spacing. Secure the tray and elbow with bolts and clamps, checking for level and alignment. Apply protective coatings to cut edges to prevent corrosion if using galvanized steel.

Verify grounding continuity and ensure all joints are properly bonded.

Additional Considerations

Maintain the minimum bend radius for the largest cable to avoid damage. Ensure adequate clearance from other services and allow for future cable additions.

Follow BS E

N 61537 and other relevant standards for safe installation. By following these steps, cable trays can be safely and efficiently routed around corners while maintaining structural integrity, cable protection, and electrical safety.