Conductor materials have undergone quite a transformation over the years. With decades of improvements and updates, today's materials are stronger and more durable than ever before.
The 1900s welcomed the development of the Aluminum Conductor, Steel Reinforced (ACSR) conductor. With this method, the core is constructed of galvanized steel conductor wires that fit into one of the following corrosion resistance categories:
The ACSR conductor replaced copper wires until growing electricity needs inspired a new manufacturing method. In the 1970s, the utility industry started utilizing a conductor design called Aluminum Conductor, Steel Supported (ACSS), created and patented by Reynolds Metals.
When manufacturing ACSS, the individual aluminum strands are annealed before stranding them around the steel core. The annealing process includes heating and cooling the aluminum to reduce tensile strength and boost conductivity.
However, the process is imperfect. The stranding method often causes irregularities, such as having strands with uneven tensile strengths and hardened aluminum. In the 1990s, a new manufacturing process called batch-annealing combatted these issues. It involves completing the annealing process after the aluminum strands go around the steel core. The method is highly beneficial for creating uniform aluminum tensile strength.
ACSS proved to be more useful than steel reinforced distribution cables in terms of tension and sag.