How to install cable tray elbows diagonally

Diagonal cable tray elbows should be installed with proper support, alignment, and bonding to ensure safe and code-compliant cable routing.

Planning and Preparation

Before installation, select the appropriate type of cable tray (ladder, ventilated trough, or solid-bottom) based on cable type, load, and environmental conditions. Measure the diagonal path carefully to determine the correct elbow angle and ensure that the bend radius does not exceed the minimum recommended for the cables being installed. Gather all necessary tools, supports, and connectors.

Support and Alignment

Cable tray elbows must be supported according to NEMA VE 2 and NEC Article 392 requirements. Supports should be positioned so that the elbow is securely held, typically near the ends of the elbow and at intermediate points if the span is long. Avoid placing connectors directly at the center of the span; instead, position them between the support point and the quarter-point of the span.

Center-hung or wall-mounted supports can be used depending on the installation environment.

Installation Steps

Attach the elbow fitting to the straight sections of the tray using the manufacturer's recommended hardware. Ensure the elbow aligns with the intended diagonal path. Secure the elbow to supports to prevent sagging or misalignment.

Use brackets or hangers rated for the tray load, considering the maximum load per hanger (typically 318–340 kg or 700–750 lbs),. Check the bend radius to ensure cables will not be stressed when pulled through the elbow. Maintain proper spacing and avoid sharp bends.

Install bonding jumpers at the elbow and along the tray to maintain electrical continuity and grounding. Ground the tray at least every 15 meters (50 ft) and at both ends.

Cable Management

After the elbow is installed, lay cables neatly, following the designated cable tray layout. Use cable ties or clamps to secure cables to the rungs or bottom of the tray, ensuring they do not obstruct airflow or exceed fill capacity. For ladder trays, cables can enter or exit from the top or bottom, but maintain the minimum bend radius to prevent damage.

Final Checks

Verify that all supports are secure and level. Ensure the elbow is properly aligned with the diagonal path. Confirm that bonding and grounding are continuous.

Check that cable spacing and fill limits comply with NEC and manufacturer specifications. By following these steps, diagonal cable tray elbows can be installed safely, maintaining structural integrity and compliance with electrical codes.