There are many myths, beliefs, and opinions in the industry on why aluminum conductors should or should not be used in certain applications. The use of aluminum conductors causes questions and concerns for many electricians, engineers, inspectors, and owners.
Aluminum has the features of low cost and low weight. Current electrical grade aluminum (Al) conductors are actually an aluminum alloy. Aluminum conductors can be round or bar shaped. Both of these shapes are used in a large majority of transmission and distribution circuits as well as industrial plants. The primary reasons for using aluminum conductors are its lower cost and low weight to conductivity ratio.
Modern aluminum alloys have been improved. Round conductor prior to the mid 1970s was made of aluminum alloy 1350, which was essentially All Aluminum Alloy Conductor. It had undesirable mechanical characteristics such as a large coefficient of thermal expansion and a susceptibility to bending and creep failure. Many fires were reported with alloy 1350. The current alloy utilized for round conductor inside buildings is the 8000 series, which became commercially available in the mid 1970s. To improve its mechanical characteristics over pure aluminum, additional elements were added to the 8000 series. In addition, it undergoes an annealing process.
Aluminum is a proven, cost effective means to conduct electricity. The issues of the early aluminum alloy 1350 have been addressed in the 8000 series alloys, the proven connection methods and the connectors in use today. Aluminum and aluminum alloys should be considered as acceptable materials for All Aluminum Conductors in power circuits provided the correct series of material is used and appropriate design, installation, and connection techniques are utilized.