Thickness Specifications for Ladder-Type Cable Trays

Ladder-type cable trays have material thickness standards that vary by duty class, tray width, and application, typically ranging from 1.5 mm to 3.0 mm for steel trays, with fiberglass and composite trays following manufacturer-specified resin-to-fiber ratios.

Material Thickness by Tray Type and Duty Class

• Steel Ladder Trays: Thickness depends on the duty class (light, medium, heavy) and tray width. Standard steel ladder trays generally have side rail thicknesses from 1.5 mm (light duty) to 3.0 mm (heavy duty). Wider trays or those with larger rung spacing may require thicker side rails to maintain load capacity and minimize deflection .
• Fiberglass/Composite Ladder Trays: Thickness is determined by the glass fiber-to-resin ratio. Pultruded components typically maintain 45–65% glass fiber by weight, while molded components range from 25–45%. These trays are designed to meet IEC 61537 standards for safe working load and deflection .
• Aluminum Ladder Trays: Aluminum trays are often thinner than steel due to higher strength-to-weight ratios, but thickness must still comply with load and span requirements. Typical aluminum side rail thickness ranges from 1.5 mm to 2.5 mm, depending on width and application .

Key Considerations

• Side Rail Height vs. Thickness: For ladder trays, side rail height and material thickness are more critical than rung spacing for load capacity . Taller side rails can allow for thinner material while maintaining strength.
• Rung Spacing: Standard rung spacing options are 6, 9, 12, or 18 inches. Wider spacing reduces overall strength, so thicker rungs or side rails may be required for wider trays .
• Environmental Factors: Corrosive environments, UV exposure, or high temperatures may necessitate thicker or specially coated materials to maintain structural integrity .
• Compliance: All ladder-type cable trays should comply with IEC 61537 for international standards or UL/NEMA standards in the U.S., which include material thickness, load ratings, and deflection limits .

Practical Guidelines

• Light-duty steel trays (up to 6–12 inches wide) typically use 1.5–2.0 mm thickness.
• Medium-duty trays (12–24 inches wide) use 2.0–2.5 mm thickness.
• Heavy-duty trays (24–48 inches wide) require 2.5–3.0 mm thickness, with additional reinforcement for very wide spans .
• Fiberglass trays should follow manufacturer specifications for resin/fiber content and UV/fire retardant additives to ensure compliance and durability .

By selecting the appropriate material thickness based on tray width, duty class, and environmental conditions, ladder-type cable trays can safely support electrical, control, and instrumentation cabling while maintaining compliance with international standards.