Width Requirements for Aluminum Alloy Cable Trays

Aluminum alloy cable trays are commonly available in nominal widths of 6, 9, 12, 18, 24, 30, and 36 inches, with the usable inside width slightly less due to side rail thickness.

Standard Widths

Aluminum cable trays are manufactured in a range of nominal widths to accommodate different cable capacities and applications. Typical widths include 6, 9, 12, 18, 24, 30, and 36 inches. These widths refer to the inside usable width, which determines how many cables can be installed while maintaining proper spacing and NEC fill compliance.

The outside width is slightly larger due to the thickness of the side rails, which is important when coordinating wall or floor penetrations or fitting trays into confined spaces (Eaton specifications, ABB catalog).

Tray Types and Width Considerations

Ladder trays: Feature two longitudinal side rails with welded rungs; widths follow the standard range and are preferred for power and large cable runs due to better airflow and easier cable pulling. Perforated or trough trays: Provide continuous bottom support with ventilation openings; usable cable area is slightly less than nominal width due to perforations. Channel trays: Narrower systems for small cable quantities or control wiring; they reach NEC fill limits faster and are not ideal for large power cables.

Wire mesh (basket) trays: Flexible and lightweight; width selection is critical for bundled cables, as load capacity depends on wire diameter and support spacing.

Additional Dimensions

Side rail height (depth): Typically ranges from 3 to 8 inches, affecting vertical stacking and heat dissipation. Rung spacing: Commonly 6, 9, or 12 inches, with radiused fittings often using 9 inches at the center of the tray width. Material thickness: Varies by duty class and affects load capacity and allowable span.

Practical Notes

When selecting aluminum alloy cable trays, consider future expansion, cable fill, airflow, and structural support. Wider trays are generally preferred over deeper trays for large power or solar DC runs to reduce cable stacking and heat concentration. Standard straight sections are available in lengths of 10, 12, 20, or 24 feet, with splice plates provided for easy connection.

By choosing the correct width and type, you ensure code compliance, safe cable installation, and long-term reliability.