Cable tray crossarm specifications and spacing

Cable tray crossarms are typically U- or L-shaped galvanized steel supports with thicknesses of 2. 5–4mm, spaced 500–1000mm apart depending on load requirements.

Material and Construction

Cable tray crossarms are generally made from Q235 low-carbon steel and are formed via rolling. Their cross-sectional shapes are usually U-shaped or L-shaped, providing structural rigidity while supporting cable trays effectively. The crossarms are hot-dip galvanized to resist corrosion, with a final passivation (chromate treatment) to seal the zinc coating and ensure long-term durability.

Dimensions and Thickness

Thickness: 2. 5mm, 3mm, or 4mm, selected based on the expected load. Length: Matches the width of the cable tray, commonly 300mm, 400mm, or 500mm.

Flange width: For heavy-load applications, the flange width may be increased to 60–80mm to enhance stiffness. Load CapacityLight-duty trays (control cables): design load ~50 N/m. Power cable trays: 150–200 N/m.

Heavy-duty scenarios (e.g., metallurgical workshops): >300 N/m, requiring stiffened crossarm structures.

Spacing and Deflection

Crossarms are typically spaced 500–1000mm apart, forming support nodes for the cable tray.

According to G

B 50217 Code for Design of Cables in Electric Power Engineering, the maximum deflection of a crossarm should not exceed L/200, where L is the support spacing. For example, a 1000mm spacing allows a maximum sag of 5mm.

Installation Notes

Crossarms are fixed to cable tray connectors using bolts. The spacing and thickness should be selected based on the type of cables, tray width, and environmental conditions. For small-diameter control and instrumentation cables, closer spacing (e.g., 500mm) is recommended to prevent drooping.

For large power cables, wider spacing may be acceptable, but the crossarm must meet the required load and deflection limits. By following these specifications, cable tray systems can maintain structural integrity, prevent excessive sag, and ensure safe and reliable cable support in industrial and commercial installations.