flashover

[ flash-oh-ver ]
/ ˈflæʃˌoʊ vər /

noun

Electricity. a disruptive discharge around or over the surface of a solid or liquid insulator.
the moment of conflagration or complete incineration caused by superheated air or combustibles.

verb (used without object)

Electricity. to have or experience a flashover.

Origin of flashover

First recorded in 1890–95; orig. noun use of verb phrase flash over

British Dictionary definitions for flashover

flashover
/ (ˈflæʃˌəʊvə) /

noun

an electric discharge over or around the surface of an insulator
the sudden and rapid spread of fire through the air, caused by the ignition of smoke or fumes from surrounding objects