How to branch cables from the main line in a cable tray

Branching cables from a main cable tray line is done using tees, crosses, or drop-outs, ensuring proper support, spacing, and compliance with electrical codes.

Planning the Branch

Before creating a branch, plan the route carefully. Identify where the branch will diverge, consider clearance, load capacity, and cable separation requirements, and ensure the main tray can handle the additional load without sagging or exceeding its rated capacity . Pre-planning helps prevent damage to cables and ensures compliance with NEC/IEC standards .

Selecting the Right Fittings

To branch from a main line, use tee or cross fittings:

• Tee fittings allow a single branch to split off at a 90° angle from the main tray.
• Cross fittings enable multiple branches to diverge from a single junction.
• Drop-outs are used when cables need to exit vertically to connect to equipment below the tray . Ensure the fittings match the tray type (ladder, ventilated trough, or solid-bottom) and are rated for the load and environment.

Installing the Branch

1. Secure the Fitting: Attach the tee, cross, or drop-out to the main tray using splice plates, bolts, or manufacturer-specific quick-connect systems . Ensure a strong mechanical connection to support the weight of the branch cables.
2. Support the Branch: Use appropriate supports such as wall brackets, trapeze hangers, or center-span supports to prevent sagging. Spacing of supports typically ranges from 1.5 to 3 meters depending on tray type and load .
3. Route the Cables: Lay cables in the branch tray carefully, maintaining proper bend radius and separation between power and data lines. Use cable ties or straps to organize and secure cables without over-tightening .
4. Grounding and Bonding: Ensure the branch tray is electrically bonded to the main tray and grounded according to code requirements to maintain safety and continuity .

Final Checks

• Verify that the branch does not overload the main tray.
• Check that all connections are secure and that cables are properly supported.
• Label the branch cables for identification and future maintenance . By following these steps, you can safely and efficiently branch cables from a main line in a cable tray system while maintaining compliance, structural integrity, and ease of future maintenance.