What wiring material was allowed for residential use due to copper shortages in the 1960s?

In the 1960s, due to significant shortages of copper, aluminum wiring became a widely accepted alternative for residential wiring. Aluminum is lighter and has better conductivity than some other materials, making it a suitable substitute for copper in many applications.

Aluminum wiring was used in residential construction as a cost-effective solution during this period, particularly for feeder and branch circuits. It’s important to note that while aluminum was widely adopted, it also brought certain challenges, such as increased risk of overheating at connections and the need for special installation techniques to ensure safety and reliability.

Materials like bronze and steel were not commonly used for electrical wiring in homes, as they do not possess the same conductive properties as copper and aluminum. Plastic, while used as an insulating material or in conduit, is not a conductive wiring material. Therefore, aluminum stands out in this context as the viable option that addressed the supply issues while allowing for effective electrical installations.