Ferranti, Sebastian Ziani de (1864-1930)

British electrical engineer who established the principle of a national grid and an electricity-generating system based on alternating current (AC) (successfully arguing against Thomas Edison's proposal). He brought electricity to much of central London. In 1881 he made and sold his first alternator.

Ferranti also designed, constructed, and experimented with many other electrical and mechanical devices, including high-tension cables, circuit breakers, transformers, turbines, and spinning machines.

Ferranti was born in Liverpool. He started his own company at 18, in partnership with Irish physicist William Thomson (Lord Kelvin), to design and manufacture the Thomson-Ferranti alternator and install lighting systems. He was chief engineer with the London Electric Supply Company 1887-92, and worked on the design of a large power station at Deptford. He set up a company in Oldham, Lancashire in 1896 to design and build all kinds of electrical equipment, most of which was designed by Ferranti himself, and to develop high-voltage systems for long-distance transmission. He was also involved with heat engines of various kinds.