Connecting aluminum wire in terminal blocks

Aluminum cable / aluminum wire as a new trend

Economic development and industrialization in most emerging countries are causing raw material prices on the world market to rise rapidly. The price ratio between copper and aluminum has risen to a factor of 1:4, which in turn makes aluminum an interesting wiring material for many industries.

The ease of handling and, in particular, the ability to install aluminum wires / aluminum cables that are up to 70% lighter make customers rethink their approach, especially when it comes to wire cross-sections larger than 16 mm². When connecting such aluminum conductors in electrical connection technology, a number of general conditions must be met to ensure that the conductor is contacted safely and with long-term stability at the clamping point.

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CONDUCTIVITY

The electrical conductivity "kappa" applies to copper (56 m/(Ω ∗ mm²)) and aluminum (36 m/(Ω ∗ mm²)).

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PRICE

The global market price ratio (as of December 2022) between copper and aluminum.

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DENSITY

The density of copper is 8920 kg/m³ and the density of aluminum is 2700 kg/m³.

Proper connection and termination of aluminum wires

Aluminum conductors for indirect connection using

- Ring cable lugs

- Press connection bolts

- Cu/Al washer (CUPAL)

Aluminum conductors for direct connection(3 steps)

- Scratching

- Greasing

- Connecting

Pretreatment and direct connection in WPD terminal blocks

**Scratching**
Scratch the oxide layer off the bare wire, for instance using a penknife.

**Greasing**
Grease the aluminum wire with a neutral grease.

**Connection**
Direct connection in the WPD terminal blocks.

Transition from aluminum to copper

Weidmuller's WPD terminal blocks enable a simple, safe and cost-effective transition from aluminum wires or aluminum cables to copper wires within the switchgear.

For example, a supply line of the switchgear can use aluminum conductors on one side of the WPD terminal block, while the other wiring on the opposite side of the terminal block is completed with copper conductors.

The pretreatment for the aluminum conductor and the required torques are stated in the corresponding product data sheets.

Terminal blocks for connecting copper and aluminum wires

Main line branch terminal blocks

Branch terminals for the installation of meter cabinets - Finger-safe distribution terminals and distribution blocks HLAK 25 and HLAK 35

Power terminal blocks - WPD

Power terminal blocks for large wire cross-sections up to 300 mm² - Compact main feed terminal for connecting aluminum wire and copper wire

PDB - Potential distribution block for DIN rails

Distribution blocks for wire cross-sections from 1.5 mm² to 185 mm² - Compact potential distribution blocks for the connection of aluminum wire and copper wire