The First Porcelain Insulator
Orville Ensign, an engineer at Edison Electric Company, which became Southern California Edison in 1909, invented the porcelain insulator. It replaced glass designs that were originally built for telegraph lines, but unable to support heavier electric wires. The porcelain “Redlands Insulator” solved this problem and was first used on the 33-kV Santa Ana River transmission line which was energized in 1899. It spanned 83 miles — the longest in the world at the time. Ensign’s design is still used today.