The curvature of a cable tray is determined by calculating the cut-out size or bend angle based on the tray width and desired angle, using simple geometric formulas.

Calculating Bend Angles

To create a bend in a cable tray, you first need to know the desired angle and the tray width. For example, if you want a 22° bend in a 600 mm wide tray:

1. Divide 90° by the desired angle to get a factor $C$: $C=90°÷22°\approx 4.09$
2. Divide the tray width $A$ by this factor to find the cut-out section $D$: $D=A÷C=600÷4.09\approx 146.7\text{mm}$ This method works for any angle and tray width, allowing you to calculate the exact section to remove for a smooth bend ( ).

Creating Multiple Bends for Larger Curves

For sweeping bends, such as a 90° turn, you can divide the total angle into smaller segments:

• Example: 90° bend in a 600 mm tray
  • Use 3 × 30° bends → 3 × 200 mm cut-outs
  • Or 2 × 45° bends → 2 × 300 mm cut-outs This approach ensures the tray curves gradually, reducing stress on cables and the tray itself ( ).

Practical Steps for Fabrication

1. Mark the centerline of the tray.
2. Measure and mark the cut-out section on either side of the centerline.
3. File or cut the lip that will be removed.
4. Fold the tray so the cuts overlap slightly, forming the desired angle.
5. Test with cardboard or scrap material first to ensure accuracy ( ).

Parallel Offsets

When routing around obstacles, you may need a parallel offset:

• Determine the offset distance and the straight-line distance over which the offset occurs.
• Divide the straight-line distance by the tray width to get a factor.
• Divide the offset by this factor to find the cut size for each set ( ).

Summary

By using these formulas and practical steps, you can calculate the curvature of cable trays accurately for any angle or offset. This ensures smooth bends, prevents cable damage, and maintains compliance with installation standards. Proper planning also allows for easier cable pulling and future maintenance.