45-degree bends in cable trays can be fabricated by cutting, marking, and overlapping tray edges using calculated offsets, or by using pre-manufactured bends for precision and safety.

Methods for Fabrication

1. Field Fabrication Using Straight Sections For wire mesh or ladder-type cable trays, 45-degree bends can be made on-site by cutting and bending straight tray sections. The process involves:

• Marking the centerline of the tray where the bend is required.
• Calculating the offset for the bend: for a 45-degree bend, take half the angle (22.5°) and measure the distance from the centerline to mark the lip that will be removed or filed away. For example, in a 100 mm tray, this may result in approximately 41.42 mm on each side .
• Cutting the tray along the marked lines and filing the lip to allow the edges to overlap.
• Bending the tray so the cut edges slide over each other, forming a precise 45-degree angle .
• Securing the bend with bolts or clamps to maintain structural integrity . 2. Using Pre-Manufactured Bends Manufacturers like Armorduct provide medium-duty flat 45-degree bends that can be bolted directly to straight tray sections. These pre-fabricated bends ensure consistent angles, maintain minimum bend radius, and reduce installation time .

Tools and Safety Considerations

• Bolt cutters or metal shears for cutting wire mesh trays .
• Files or grinders to smooth cut edges and remove sharp burrs.
• Protective caps for exposed ends to prevent cable damage.
• Measuring tools to ensure accurate angles and offsets.
• Always follow manufacturer guidelines and local electrical codes (e.g., NEC 392.18) for field bends .

Minimum Bend Radius

While ladder and solid-bottom trays do not have a strict NEC-specified minimum radius, manufacturers often provide recommended radii to prevent cable damage. For example, metallic ladder trays may have bends available in radii of 12”, 24”, 36”, or 48” . Field-fabricated bends should aim to approximate these radii where possible to facilitate cable pulling and avoid sharp kinks.

Tips

• Practice on cardboard or scrap material before cutting actual trays to verify measurements and angles .
• Use rubber or plastic end caps to protect cables from sharp edges.
• Consider pre-fabricated bends for complex installations with multiple angles to save time and ensure uniformity. By combining accurate measurement, proper cutting, and secure assembly, 45-degree cable tray bends can be fabricated efficiently while maintaining safety and functionality.