Complete List of Cable Tray Numbers

Cable tray numbers typically represent the tray's width, depth, or load class, indicating its size and load-carrying capacity.

Tray Width and Depth

Cable tray numbers often correspond to standard widths and depths. For example, in metric systems per IEC 61537, common widths include 50, 75, 100, 150, 200, 225, 300, 400, 450, 500, 600, 750, 900, and 1000 mm, while standard depths are 25, 50, 75, 100, 125, and 150 mm . In the U.S., NEMA VE 1 standards list widths such as 6, 9, 12, 18, 24, 30, and 36 inches with depths of 3, 4, 5, and 6 inches . These numbers help installers select trays that provide adequate space for cables while maintaining proper fill percentages and ventilation.

Load Class or Structural Rating

Some cable tray numbers indicate the load-carrying capability, also called the Load Class. This designation reflects the maximum working load the tray can support over a specific support span. For example, a ladder tray labeled with a certain number may be rated for heavier power cables or longer unsupported spans, guiding engineers in selecting the most economical and safe system for the installation .

Practical Implications

• Cable fill compliance: The tray number helps determine if the tray can accommodate the planned number and size of cables without exceeding NEC or IEC fill limits .
• Heat dissipation: Wider or deeper trays allow better airflow, reducing overheating risks.
• Future expansion: Selecting a tray with a larger width or higher load class ensures room for additional cables.
• Code compliance: Standardized numbers ensure compatibility with fittings, covers, and supports, and adherence to NEC, NEMA, and IEC requirements . In summary, cable tray numbers are a shorthand for the tray's physical dimensions and/or structural capacity, helping engineers and installers choose the correct tray for safe, code-compliant, and expandable cable management.