Large metal chisel used to test a live 10,000-volt Ferranti cable at Deptford Power Station in 1889.

By the 1880s, electric lighting was the must-have innovation for any self-respecting town. Giants of electricity Tesla, Edison and Westinghouse fought a battle of the currents over the safe transmission of high voltage electricity from power station to customer.

Sebastian Ziani de Ferranti built the world’s first central power station at Deptford. He used alternating current (AC) to power London.

In 1889 the battle of the currents got serious. Thomas Edison claimed that wasn’t safe. Sebastian Ziani de Ferranti responded with a live safety test.

Deptford’s site foreman drove a metal chisel into a live 10,000-volt cable. Assistant engineer H. W. Kolle held the chisel and could have been electrocuted. The chisel broke the cable and triggered the main fuse, as Ferranti knew it would.