How to lay cables when the cable tray has a 45-degree bend

When laying cables through a 45-degree bend in a cable tray, use a smooth transition with proper bend radius, secure supports, and avoid exceeding cable fill limits to prevent damage and maintain system reliability.

Use Factory-

Made or Custom BendsWhenever possible, use factory-manufactured 45-degree bends. These provide a smooth curve that allows cables to pass without sharp kinks or excessive stress, reducing the risk of insulation damage and maintaining proper bend radius. If a custom bend is required, carefully cut and fold the tray: mark the centerline, file or remove the lip where necessary, cut along the line, and fold so the edges overlap to form the 45-degree angle.

Maintain Proper Cable Bend Radius

Cables should not be bent tighter than their minimum bend radius, which is typically specified by the manufacturer. A 45-degree bend is generally easier for pulling cables than a 90-degree bend, but care must be taken to avoid sharp edges on the tray that could damage insulation.

Support and Secure the Tray

Ensure the tray is properly supported near the bend. Use wall mounts, cantilever arms, or trapeze hangers depending on the installation location. Supports should be close enough to prevent sagging, which can pinch or stress cables.

For metal trays, consider expansion splice plates if the tray is long or exposed to temperature changes, allowing slight movement without stressing the cables.

Cable Layout and Fill

Organize cables in layers, keeping similar types together. Do not exceed 40% of tray capacity to allow airflow and prevent overheating. Secure cables at regular intervals using ties or clamps to prevent shifting during installation.

Cutting and Painting

If cutting the tray to create a custom bend, protect exposed metal edges with cold-galvanizing spray to prevent rust and maintain structural integrity. Always test the bend with a cardboard mock-up before working with the actual tray to ensure accuracy.

Summary

Prefer factory-made 45-degree bends for smooth cable routing. Maintain minimum bend radius for all cables. Support the tray adequately near bends to prevent sagging.

Organize and secure cables, keeping fill below recommended limits. Protect cut edges and test bends before final installation. Following these steps ensures a safe, reliable, and code-compliant cable tray installation through 45-degree bends, minimizing the risk of cable damage and facilitating future maintenance.