flashover

Deverbal from flash over.

flashover (countable and uncountable, plural flashovers)

1. The near simultaneous ignition of all combustible material in an enclosed area.
2. An unintended electric discharge or arc over or around an insulator.

   Synonym: sparkover

   • 1960 April, “Talking of Trains: Safety with 25kV a.c.”, in Trains Illustrated, page 203:

     The overhead line was energised at 25,000 volts and the height of the contact wire was reduced to 11 in. above the chimney, then to 5 and finally to 2 in.; at this last, short distance the flashover occurred, but all the men were perfectly safe because the current went direct to earth through the locomotive.

• flashover voltage