Why Are Bimetallic Terminal Blocks So Common In Electrical Distribution Cabinets?

At power distribution construction sites, we often encounter situations where aluminum cables need to be connected to copper busbars. Simply twisting these two metals together will inevitably lead to problems over time. That's when bimetallic lugs comes in handy. The technical logic behind this small component is actually quite straightforward: the bi metal cable lug can reliably connect aluminum conductors to copper devices, building a stable bridge between the two materials.

The Awkwardness of Aluminum Cables Meeting Copper Interfaces

Everyone knows that copper and aluminum have different properties. Aluminum wire is cheap and lightweight, and is widely used in large-section power transmission; however, most equipment terminals are made of copper. If there is direct contact, moisture can easily enter, causing a chemical reaction and a significant increase in contact resistance. The purpose of using bi metal lugs connectors is to nip this potential problem in the bud.

How exactly does this terminal work?

The structure of this terminal is quite interesting. It's not a simple assembly, but rather a friction welding process that tightly bonds the copper and aluminum together.

• Aluminum tube side: Specifically designed to accommodate the aluminum conductor, with dimensions that perfectly match the aluminum wire.

• Copper side: This end connects perfectly to copper busbars or switchgear, with identical material properties.

• Transition zone: There are no gaps at the copper-aluminum interface, allowing for very smooth current flow.

The bi metallic cable lugs allows for a reliable connection of aluminum conductors to copper equipment, a design that combines the lightweight nature of aluminum wire with the stable performance of copper equipment.

The intricacies of construction

When installing bimetal cable lug, craftsmanship is quite important. Peel off the oxide layer of the aluminum wire, apply conductive paste, and then compact it with hydraulic clamps. This series of actions, combined with the material of the terminal itself, ensures stable circuit operation over extended periods. This method is much more durable than earlier, simpler transition methods and is now widely accepted in factory and building power distribution.