Some homes built in the late 60′s and early 70′s were wired with aluminum wire as a way to lower costs due to the amount of copper needed for the war. Aluminum is actually a very good conductor of electricity. Power companies use it for transmission lines. They mix it with steel for strength. While good for some applications it is a hazard when used for branch circuits. A branch circuit is a 120 volt receptacle circuit, lighting circuit or small 120 volt appliance circuit. Aluminum wire requires periodic maintenance to remain in safe condition and the number of connections in a branch circuit can be more than 60 in a single branch circuit.
Aluminum is fine for use as service entrance conductors or feeders or large appliance circuits.
Some insurance companies are no longer writing policies on homes wired with aluminum. They are requiring homes to be rewired or a special tool is used to crimp copper onto the ends of the wires to be reconnected to the devices. This method is safe when done with a special tool that most electrical contractors cannot afford. Some electricians will use wirenuts made to connect aluminum to copper but these are know to fail and cause fires, DO NOT accept this method as a repair. It is our opinion a rewire is the best choice. Although it is one of the most expensive home repairs a rewire will last for a long time and provide comfort and safety.