2010 Commencement of Sales of Aluminum Wiring Harnesses

In 2010, Sumitomo Electric launched sales of aluminum automotive wiring harnesses. A wiring harness refers to an assembly of electric wires for power supply and signal transmission. In line with the increasing functionality of vehicles, the number of electronic devices built into vehicles has been increasing. Wiring harnesses connect these devices to supply electricity and transmit signals throughout a vehicle.

The Sumitomo Electric Group started the development and production of wiring harnesses immediately after the end of WWII. In the 1960s, the Company rapidly expanded production due to the high economic growth period of Japan and resultant motorization.

Recently, the auto industry has been working to reduce energy consumption and improve fuel efficiency in order to cut CO2 emissions, which has become a social and global issue. It was essential to reduce the weight of the vehicle body in line with the improvement of engine combustion efficiency. In general, copper electric wires are used for wiring harnesses due to their superb conductivity. To meet the needs of reducing the weight of the vehicle body, the Sumitomo Electric Group developed aluminum alloy electric wires exclusively for automotive use by achieving high strength and conductivity. It succeeded in halving the weight while maintaining current-carrying capacity equivalent to that of copper electric wires. When the product was released in 2010, the anti-vibration performance was inferior to that of copper electric wires. The scope of application was limited to interior wiring, such as doors, and instrument panel wiring around the driver’s seat.

In 2015, the Sumitomo Electric Group succeeded in the development of high-strength aluminum alloy electric wires, whose strength was superior to that of copper electric wires, by taking full advantage of its engineering capabilities. This made it possible to use aluminum wiring harnesses in areas subject to severe vibration, including the area around the engine. Aluminum wiring harnesses contribute to weight reduction and resource conservation because the reserves of aluminum are several times larger than that of copper.