National Standard Thickness of Electrical Cable Trays

The standard thickness of electrical control cable trays varies by material and duty class, typically ranging from 1.2 mm to 2.5 mm for steel trays, with aluminum and nonmetallic trays following manufacturer and NEMA/IEC guidelines.

Material and Duty Class Considerations

Steel Cable Trays: For galvanized or stainless steel trays, thickness is determined by the tray's duty class (light, medium, or heavy) and load requirements. Light-duty trays often have a thickness around 1.2–1.5 mm, medium-duty trays around 1.5–2.0 mm, and heavy-duty trays 2.5 mm or more to support higher cable loads and longer spans, in accordance with ASTM A653 and NEMA VE 1 standards . Hot-dip galvanization adds a protective zinc layer, whose thickness is proportional to the base metal thickness, enhancing corrosion resistance . Aluminum Cable Trays: Aluminum trays are generally lighter and corrosion-resistant, with thicknesses slightly lower than steel for equivalent load ratings. Typical aluminum tray thickness ranges from 1.2 mm to 2.0 mm, depending on alloy and structural design, following NEMA VE 1 and manufacturer specifications . Nonmetallic (Fiberglass/Plastic) Trays: Nonmetallic trays, such as fiberglass reinforced polyester, are designed according to UL 568 and NEMA FG 1 standards. Thickness is determined by mechanical strength and span requirements, often ranging from 6 mm to 12 mm, depending on tray width and load .

NEC and IEC Guidelines

• NEC Article 392 governs cable tray installations, including ladder, ventilated, and solid-bottom trays, and specifies that tray thickness must support the intended cable load while maintaining safety and structural integrity .
• IEC 61537 provides international standards for both metallic and nonmetallic trays, including thickness requirements based on load class and environmental conditions .

Practical Recommendations

• Always select tray thickness based on load, span, and environmental conditions rather than solely on nominal material thickness.
• For control cables, NEC recommends a 50% fill ratio, which affects tray selection and may influence the required thickness to prevent sagging or deformation .
• Verify compliance with local codes and manufacturer specifications, as thickness requirements may vary slightly depending on corrosion protection, tray type, and installation environment. By adhering to these standards, electrical control cable trays will provide safe, durable, and code-compliant support for control and power cables.