Aluminum Branch Wiring

During the 1960s and 1970s, aluminum wiring was often used in homes as a cost-effective alternative to copper wiring. Aluminum is a good conductor of electricity and was much cheaper than copper, making it an appealing option for use in homes.

However, problems began to emerge with aluminum wiring. Over time, it was found that aluminum tends to oxidize when exposed to air, creating a coating of aluminum oxide on the wire. This oxide is a poor conductor of electricity and can cause increased resistance, leading to overheating. This can pose a significant fire hazard.

Additionally, aluminum wiring has a different thermal expansion rate than copper. This means that when it heats up (as it naturally does when electricity is flowing through it), it expands more than copper. When it cools down, it contracts more. Over time, this can cause connections to become loose, leading to arcing and potentially causing fires.

Also, when aluminum is connected to other metals (such as copper or steel, which are often used in electrical devices and fixtures), galvanic corrosion can occur. This can cause further issues with overheating and fire risk.

For these reasons, aluminum branch wiring is considered to be problematic and a potential safety hazard. In some places, it may not be up to current code. If a home has aluminum wiring, it is often recommended that the wiring be inspected by a qualified electrician. Solutions can range from applying antioxidant paste on the connections, pig-tailing copper wires to the ends of the aluminum wires, or completely replacing the aluminum wiring with copper.

It’s important to note that not all aluminum wiring is problematic – aluminum is still used for certain types of wiring (like service entrance wiring) where these issues aren’t as prominent. The problem is most pronounced with smaller gauge branch circuit wiring.

If you’re considering purchasing or currently live in a home built in the 1970s with aluminum wiring, I would highly recommend having an inspection conducted by a qualified electrician. They will be able to identify any potential problems and recommend the best course of action.

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