Methods for rounding corners of cable trays

Corners of cable trays can be rounded using field bending, strategic cuts, or prefabricated fittings while maintaining proper bend radius and NEC compliance.

Field Bending and Cutting

For wire mesh cable trays, installers often perform on-site bending to navigate 90-degree turns or irregular angles. This involves making strategic side cuts in the tray and carefully bending the mesh to form a smooth corner transition. Maintaining the minimum bend radius is crucial to prevent damage to Ethernet, fiber, or power cables and to ensure proper cable performance and longevity (ShowMeCables) . After bending, verify grounding and bonding to maintain electrical safety.

Using Prefabricated Fittings

Many cable tray systems, especially ladder or solid-bottom trays, offer factory-made corner fittings such as elbows or radius bends. These fittings provide a uniform bend radius and reduce the risk of cable stress or overfilling at corners. They are particularly useful in high-density installations or where aesthetics and cable management are important (BEAMA Guide) .

Maintaining Proper Bend Radius

Regardless of method, it is essential to avoid sharp bends. The bend radius should generally be at least 6 to 9 inches (150–230 mm) for standard cable trays, depending on cable type and size. For armored cables (SWA), allowing a section of cable in free air around the bend can help prevent kinking or damage (Electricians Forums) .

Tools and Techniques

• Hand tools: Pliers, hammers, or bending jigs for small adjustments in mesh trays.
• Mechanical benders: For larger ladder or solid trays, mechanical benders ensure consistent radius.
• Cutting tools: Hacksaws or angle grinders for making precise side cuts in mesh trays.

Compliance and Safety

All modifications must comply with NEC Article 392 and relevant standards (BS EN 61537 for ladder/tray systems). Ensure that trays are not overfilled at corners, and that cables are properly supported to prevent strain or damage (ShowMeCables, Eaton Cable Tray Manual) . By combining field bending, prefabricated fittings, and careful radius management, installers can achieve smooth, safe, and code-compliant corner transitions in cable tray systems.