Dimensions of Composite Cable Trays

Composite cable trays, such as fiberglass ladder-type trays, typically have widths from 50 mm to 1000 mm and nominal depths ranging from 2 inches (51 mm) to 9 inches (229 mm), with material thickness and span ratings designed for structural and electrical compliance.

Standard Widths and Depths

Composite cable trays are manufactured in a range of nominal widths to accommodate different cable loads and installation requirements. Standard inside widths generally range from 50 mm to 1000 mm (2 to 36 inches), with narrower trays (100–150 mm) used for instrumentation and control wiring, medium widths (300–600 mm) for general power distribution, and wider trays (>600 mm) for heavy industrial or data center applications. The nominal depth (side rail height) controls vertical stacking capacity and heat dissipation.

Common depths for composite ladder-type trays include 2” (51 mm), 3” (76 mm), 5” (127 mm), 7” (178 mm), and 9” (229 mm). Depth selection depends on cable fill requirements, NEC or IEC fill ratios, and thermal considerations.

Material Thickness and Construction

Composite trays are typically made from fiberglass reinforced plastic (FRP) using pultrusion, compression molding, or resin transfer molding. Pultruded components maintain a glass fiber to resin content of 45–65% by weight, while molded components range from 25–45% glass fiber. All materials are fire retardant with a Class 1 flame spread rating (≤25 per ASTM E-84) and may include UV inhibitors and conductive additives for static dissipation.

Span and Load Considerations

The safe working load (SWL) and maximum span are specified according to IEC 61537. Load vs. span is based on maximum deflection at mid-span for a single span installation, with continuous spans or different support points potentially allowing higher load ratings. Proper selection ensures structural integrity and compliance with electrical codes.

Summary

When selecting composite cable trays, consider: Width: 50–1000 mm (2–36 inches) depending on cable type and quantityDepth: 2–9 inches (51–229 mm) for vertical stacking and heat dissipationMaterial: FRP with specified glass fiber content, fire retardant, UV resistantSpan/Load: SWL per IEC 61537, adjusted for installation conditions These dimensions ensure code compliance, structural reliability, and long-term performance in industrial, commercial, and utility installations.