What size cable tray should be used for a 90 cable

For a 90° cable tray fitting, the tray width and depth must match the straight sections, with specific limitations depending on tray type and thickness.Key Considerations for 90° FittingsWhen selecting a 90° cable tray fitting, the following factors are critical:Tray Width and Depth: The fitting should match the width and depth of the straight tray sections to maintain proper cable fill and structural integrity. For example, standard widths range from 100 mm to 900 mm, and depths vary depending on cable load and airflow requirements .Material Thickness: Thicker trays support heavier loads. For pan trays, 1.0 mm thickness is typically available only up to 300 mm width, and 90° inside flanges are not available on smaller tray heights like 025 or 050 .Tray Type: Ladder trays prioritize width and side rail height for heavy loads, while perforated or pan trays balance containment with ventilation. Wire mesh trays offer flexibility but lower structural capacity .Cable Fill Compliance: NEC and NEMA standards limit tray fill to a percentage of usable area, usually around 40%, to prevent overcrowding and heat buildup .Practical GuidelinesMatch the Fitting to the Straight Section: Ensure the 90° fitting has the same inside width and usable depth as the adjoining straight tray.Check Material and Load Ratings: Verify that the fitting's thickness and load class can support the cable weight over the span.Allow for Cable Bending Radius: At 90° bends, maintain proper bend radius to avoid damaging cables. Larger widths may be required for high-density cable runs.Use Standardized Fittings: Most manufacturers provide 90° elbows compatible with their tray systems, ensuring code compliance and ease of installation .ExampleFor a pan tray with a 300 mm width and 1.0 mm thickness, a 90° inside flange fitting is available, but for widths above 300 mm, thicker material and different flange designs may be required . Ladder trays and perforated trays follow similar sizing rules but may have different load and depth specifications. By following these guidelines, you can ensure that your 90° cable tray fitting is structurally sound, code-compliant, and suitable for the intended cable load.