Low-voltage connection busbar trunking

Low-voltage busbar trunking systems are connected using modular trunking units and tap-off units, ensuring electrical continuity, mechanical stability, and compliance with BS EN 61439-6 standards. Connection OverviewLow-voltage busbar trunking systems consist of distribution runs and feeder runs. Distribution runs deliver power over a predetermined area, while feeder runs interconnect switchboards or connect a switchboard to a transformer.

Connections are made using busbar trunking units (BTUs) and tap-off units, which allow power to be drawn at defined positions along the trunking system, typically through an overcurrent protective device.

Step-by-

Step Connection Method

Preparation and InspectionVerify that all components match the project layout and delivery documentation. Inspect busbar units for damage and ensure all insulation and mechanical parts are intact.

Mechanical Alignment and Fixing

Align busbar units end-to-end according to the layout. Use the manufacturer-specified mechanical connectors and fixings to secure units. Ensure minimal fixings per meter while maintaining mechanical stability, as busbar trunking is designed for long runs with fewer supports than conventional cabling.

Electrical Connection

Connect busbar conductors using factory-supplied jointing kits or bolted connectors. Ensure proper torque on all bolted connections to maintain electrical continuity and prevent overheating. Verify phase sequence and polarity before energizing the system.

Tap-

Off Unit InstallationTap-off units are installed at predefined positions along the trunking. Each tap-off unit typically includes a protective device (MCB or MCCB) to isolate the downstream load. Units are mechanically secured and electrically connected to the main busbar using the manufacturer's recommended procedure.

Earthing and Bonding

Ensure all metallic parts are properly earthed. Bonding between trunking sections is critical to maintain safety and reduce electromagnetic interference.

Testing and Commissioning

Perform insulation resistance and continuity tests before energizing. Verify that tap-off units operate correctly and that the system meets the rated current and voltage specifications.

Advantages of Proper Connection

Reduced installation time compared to multiple cable runs. Flexibility to reposition or add tap-off units. Mechanical strength over long runs with minimal fixings.

Compliance with international and national standards, including BS EN 61439-6. By following these connection methods, low-voltage busbar trunking systems provide a safe, extendable, and efficient solution for power distribution in industrial, commercial, and residential buildings.