Requirement for 35-degree angle of cable tray bend

A 35-degree cable tray bend requires consideration of cable minimum bending radius, proper support, and potentially adjustable or custom elbows to ensure safe installation.

Bend Angle and Fittings

Standard cable tray fittings are typically available for 30°, 45°, 60°, and 90° bends. Since 35° is not a standard angle, you can use adjustable elbows or fabricate a custom bend to achieve the required angle while maintaining proper cable support and alignment. Adjustable elbows allow flexibility in installation and help accommodate non-standard angles without compromising cable integrity.

Minimum Bending Radius

Cables must not be bent more sharply than their minimum bending radius, which depends on the cable type, insulation, and diameter. The minimum bending radius is usually expressed as a multiple of the cable's overall diameter (e.g., 4D, 5D, or 6D). For example, a cable with a 21 mm diameter and a 4D requirement would need a bend radius of at least 84 mm.

Ensuring the bend radius is respected prevents insulation damage, conductor stress, and potential electrical faults.

Support and Installation

At bends, especially non-standard angles like 35°, it is important to add supports to the tray to maintain structural integrity and prevent sagging. Supports should be placed according to CSA/NEMA VE2 or equivalent guidelines, typically near the start and end of the bend, and at intervals along the tray as needed. Proper support also facilitates easier cable pulling and reduces mechanical stress on the cables.

Summary of Best Practices

Use adjustable elbows or custom bends for non-standard angles. Ensure the minimum bending radius of all cables is maintained. Provide adequate support at the bend to prevent sagging and stress.

Follow relevant standards such as BS EN 61537, CSA/NEMA VE2, or manufacturer guidelines for installation. By following these requirements, a 35-degree cable tray bend can be safely implemented without compromising cable performance or structural integrity.