Spacing of crossbars in trapezoidal cable trays

The recommended spacing of crossbars (rungs) in trapezoidal cable trays is typically 150 to 230 mm (6 to 9 inches), depending on cable type and application.Recommended Crossbar SpacingFor trapezoidal cable trays, the crossbars or rungs are designed to support cables while allowing proper ventilation and preventing sagging. The typical spacing is:Instrumentation and control cables: 150–230 mm (6–9 inches) to provide adequate support and protection for smaller, sensitive cables .Power and general-purpose cables: Spacing may be slightly wider depending on cable weight and tray load, but should ensure that cables do not sag or touch the tray bottom excessively .Factors Affecting SpacingCable Type and Size: Heavier or larger cables require closer crossbar spacing to prevent sagging and maintain mechanical integrity.Tray Material and Strength: Steel, aluminum, or fiberglass trays have different load capacities; stronger materials may allow slightly wider spacing.Environmental Conditions: High temperatures or outdoor exposure may require closer spacing to maintain cable stability and prevent excessive deflection.Maintenance and Access: Adequate spacing ensures easy inspection, cable replacement, and airflow for heat dissipation .Support Span ConsiderationsHorizontal support span: For straight runs, supports are typically placed every 1.5 to 3 meters, depending on tray type and load .Vertical spacing: When stacking trays, maintain a minimum of 150 mm between upper and lower trays to allow ventilation and prevent interference .Best PracticesEnsure crossbars are aligned and securely welded or bolted to maintain tray integrity.For shielded power and signal cables, spacing may be adjusted to reduce electromagnetic interference while still providing mechanical support .Follow manufacturer guidelines and applicable standards such as NEMA VE-1/VE-2 or BS EN 61537 for compliance and safety . By adhering to these spacing recommendations, trapezoidal cable trays will provide structural stability, proper cable support, and efficient heat dissipation, ensuring long-term reliability of the cable installation.