How to route a 185mm cable in a cable tray

A 185mm cable should be routed in a properly sized cable tray with adequate support, spacing, and bend radius to ensure safety, prevent overheating, and comply with standards.

Tray Selection and Sizing

For a large 185mm cable, select a ladder-type or ventilated trough tray that can accommodate the cable diameter and weight while allowing airflow for heat dissipation . Ensure the tray width and depth are sufficient so that the cable fill does not exceed 40% of the tray capacity, which prevents overheating and maintains long-term performance . Calculate the total cross-sectional area of the cable and compare it to the tray's allowable fill according to NEC 392.22 for mixed-use trays .

Support and Mounting

Install the tray using supports spaced appropriately, typically 1.5 to 3 meters apart, depending on the tray type and cable weight . For heavy cables like 185mm, shorter spacing (1.5m) is recommended to prevent sagging and mechanical stress . Use wall mounts, cantilever arms, or trapeze hangers as needed, ensuring the tray is level and straight before securing .

Cable Routing and Bend Radius

• Maintain the minimum bend radius specified by the cable manufacturer to avoid insulation damage. For large power cables, this is usually 10–15 times the cable diameter .
• Lay the cable in an organized, controlled manner, avoiding sharp bends or kinks .
• Use cable rollers or guides for long runs to reduce friction and mechanical stress during installation .

Securing and Labeling

• Fix the cable at regular intervals using approved clamps or ties to prevent movement .
• Label the cable clearly for identification and maintenance purposes .
• Ensure proper segregation of power and control cables if multiple services share the tray .

Compliance and Safety

• Verify that the tray and cable installation meet NEC/IEC standards, including grounding and bonding requirements .
• Consider fire-rated barriers if the cable passes through walls or floors to prevent fire spread .
• Avoid overloading the tray mechanically or electrically to maintain system reliability . By following these steps—selecting the right tray, calculating fill, maintaining proper bend radius, supporting the cable adequately, and ensuring compliance—you can safely and efficiently route a 185mm cable in a cable tray system.