Why can't copper and aluminum wires be directly connected?
hmwadeseo > 07-25-2024, 08:25 AM
Copper and aluminum wires cannot be directly connected due to the risk of galvanic corrosion. When two dissimilar metals come into contact in the presence of an electrolyte, such as moisture or condensation, an electrochemical reaction can occur. This reaction causes one of the metals to corrode at a faster rate, leading to the gradual deterioration of the electrical connection over time.
The specific issue is that copper and aluminum have different positions on the galvanic series, which measures the relative reactivity of metals. Copper is less reactive than aluminum, meaning aluminum will act as the anode and corrode preferentially when the two metals are connected. This can result in high resistance connections, arcing, and even complete failure of the electrical circuit.
To safely connect copper and aluminum wires, an intermediary material, such as a bimetallic connector or a compression terminal, must be used. These connectors provide a barrier between the dissimilar metals and prevent direct contact, mitigating the risk of galvanic corrosion. Proper installation techniques, such as cleaning the wire surfaces and applying anti-oxidant compounds, are also important to ensure a reliable long-term connection.