FAA Powerplant Written Practice Test

When using hand crimped wire terminals, which type of terminals is recommended for aluminum wire?

1. Brass terminals

2. Plastic terminals

3. Only aluminum terminals

4. Copper terminals

The correct answer is: Only aluminum terminals

The recommendation for using only aluminum terminals with aluminum wire is based on the principle of avoiding galvanic corrosion. When dissimilar metals are connected, such as aluminum and copper, it can lead to corrosion at the junction due to electrolysis. This corrosion can degrade the connection over time, potentially leading to failure. Aluminum wire has different thermal and electrical characteristics compared to copper and requires terminals that are engineered for its specific properties. Aluminum terminals are designed to ensure a secure and stable connection that accommodates the expansion and contraction of the aluminum wire when it is subjected to temperature changes. This not only enhances the reliability of the electrical connection but also prolongs the lifespan of the terminal and wire system. Using brass or copper terminals with aluminum wire introduces the risk of corrosion and other issues related to thermal expansion differences, which can compromise the integrity of electrical connections. Likewise, plastic terminals do not provide the necessary conductivity for effective electrical connections, further reinforcing the importance of using aluminum terminals when dealing with aluminum wire.