How to bridge cable tray connections

Bridging cable trays involves using junction bridges and appropriate clips to connect trays at tees or crosses, ensuring smooth cable transitions and preventing kinking or bunching.

Understanding Cable Tray Bridges

Cable tray bridges are used to span junctions, tees, or cross points in a cable tray system. They maintain proper cable separation and allow cables to transition smoothly between intersecting trays, which is essential for signal integrity and preventing physical damage to the cables.

Required Hardware

Junction Bridges: Pre-designed components that fit over the intersection of trays. Bridge Clips (e.g., BC1): Used to secure the bridge to the tray junction hardware. Mounting Hardware: Bolts and slots (e.g., BH75 Bridge horn mounting holes) to attach the bridge securely.

Cable Fasteners: Nylon zip ties or similar to hold cables in place on the bridge.

Installation Steps

Plan the Layout: Identify all junctions, tees, and cross points where bridging is required. Ensure the cable tray system is properly supported and aligned according to design specifications. Position the Bridge: Place the junction bridge over the intersection of the trays.

Ensure it aligns with the trays and provides a smooth path for cables. Secure the Bridge: Use the bridge clip (e.g., BC1) and bolts to attach the bridge to the tray junction hardware (e.g., CE35 or EZT90/RADT90). Make sure the bridge is stable and level.

Install Cables: Lay the cables over the bridge, maintaining proper separation and avoiding sharp bends. Use nylon zip ties through the predrilled slots to secure the cables without compressing them. Check Continuity and Support: Ensure the bridge and trays maintain electrical continuity if required and that the support spacing meets load requirements.

Standard support spacing for ladder trays is typically up to 3. 6 meters, with a maximum load per hanger around 318–340 kg.

Best Practices

Respect Bending Radius: Ensure the bridge and tray accessories accommodate the minimum bending radius of the largest cable to prevent damage. Maintain Accessibility: Leave sufficient clearance above and between trays (around 300 mm) for cable installation and maintenance. Follow Safety Codes: Adhere to NEC Article 392 or local electrical codes for grounding, bonding, and support requirements.

Avoid Overloading: Consider future cable additions when calculating load capacity for the bridge and tray system. By following these steps and using the correct hardware, bridging cable trays can be done safely and efficiently, ensuring long-term reliability and ease of maintenance.