Cable Tray Load-Bearing Specifications and Dimensions Table

Cable trays are designed with specific load classes, widths, rung spacing, and span limits to safely support electrical cables, with specifications varying by material and manufacturer. Key Specifications1.

Tray Types and Materials

Ladder Tray: Two longitudinal side rails with transverse rungs; supports heavy cable bundles; typically made of steel (galvanized, stainless, or painted) or aluminum.

Wire Mesh/

Basket Tray: Open mesh design; lighter loads; allows ventilation and easy cable access. Solid Bottom Tray: Enclosed base; used for sensitive cables or where drip protection is required. 2.

Standard Dimensions

Widths (inside rail to inside rail): 150 mm, 203 mm, 300 mm, 450 mm, 600 mm, 750 mm, 900 mm. Rung Spacing: 150 mm, 225 mm, 300 mm; ventilated openings up to 52 mm for airflow. Tray Lengths: Standard straight sections of 3 m or 6 m; extended lengths of 9.

1 m and 12. 2 m available. Side Rail Thickness: Typically 16 gauge steel tubing for ladder trays.

3.

Load-

Bearing and Span ConsiderationsLoad Class: Defines maximum load for a given support span; affects tray design and cost. Safe Working Loads: Based on continuous tray over four spans or more; deflection limited to SPAN/200 for worst-case end span. Span Limits: Vary by tray width and material; wider trays may experience local deflection across the base, which is structurally acceptable but may affect appearance.

I-

Beam vs.

C-

Shape: Ladder trays with I-beam rungs provide 15–20% more strength than C-shape designs. 4. Regulatory ComplianceUL Listings: UL CYNW for ladder trays; NEMA VE 1 compliance.

CSA/NEC Compliance: Canadian and U. S. electrical codes for ladder tray installation. Grounding and Bonding: Must comply with NFPA 70 Sections 392.

60(A) and 392. 60(B),. 5.

Installation Notes

Trays can be mounted on floors, walls, ceilings, or equipment racks. Use splice plates, bolts, nuts, and washers for connecting units. Support spacing and deflection must be considered for both mechanical performance and visual appearance.

Example Load Table (Indicative)Tray Width (mm)Max Load (kg/m)Max Span (m)Rung Spacing (mm)1505031503001003225450150330060020033009003003300Note: Actual load capacities vary by manufacturer, material, and finish; consult specific load tables from Hubbell, Metsec, Unitray, or Eaton for precise values. This information provides a comprehensive reference for selecting cable trays based on load requirements, dimensions, and installation conditions.