There are obviously materials property differences, such as, capacity, weight, and cost between aluminum (Al) and copper (Cu) to consider for an electrical application. Al was more prevalent in the past for products such as bus bars, fuses, and breakers. Overtime, some designers have changed components from Al to Cu. Today, due to cost stability and coating some designers are switching back.
Misconceptions about the properties between Al and Cu can arise due to different grades of metals used in different electrical applications. The Cu used in wire and electrical equipment is nominally pure. Pure Al, however, is often not strong enough for electrical applications. Also, keep in mind that different alloys have changed over time and on account of evolving applications.