How to change the diameter of a trapezoidal cable tray

To change the diameter (or internal width) of a trapezoidal cable tray, you need to modify its size settings in your design software or select a tray with the appropriate dimensions based on cable fill calculations.Modifying Cable Tray Size in Design Software

If you are using CAD or BIM software like Autodesk Revit or AutoCAD MEP:

1. Access Electrical Settings: Go to the Manage tab, select MEP Settings, and open Electrical Settings.
2. Select Cable Tray Settings: In the Electrical Settings dialog, expand Cable Tray Settings and click on Size.
3. Modify Size: Choose the trapezoidal tray you want to adjust, click Modify Size, and enter the new internal width or diameter. Confirm the changes to update the tray throughout your project .
4. Bulk Changes: For multiple trays, you can apply filters to select all relevant trays and modify their dimensions in bulk, ensuring consistency across the design .

Determining the Correct Diameter

The “diameter” in a trapezoidal tray usually refers to the usable internal width or depth that determines cable capacity. To select the correct size:

• Calculate Cable Fill: Use the actual outer diameter of each cable and the number of cables to compute the total cross-sectional area.
• Check Standards: Ensure the tray size complies with IEC 61537 or NEC Article 392, which define maximum fill percentages and spacing requirements .
• Select Tray Type: Ladder, perforated, solid-bottom, or wire mesh trays affect ventilation and fill capacity. Trapezoidal trays are often used for power cables where heat dissipation is critical .

Practical Tips

• Maintain a design fill target around 40–50% to allow for future expansion and proper heat dissipation.
• Verify that the modified tray dimensions do not interfere with supports, bends, or other fittings.
• Always cross-check with manufacturer specifications to ensure structural integrity and compliance. By combining software modification with engineering calculations, you can safely and efficiently adjust the diameter of trapezoidal cable trays to meet project requirements.