1) disruptive discharge 2) flashover 3) sparkover the passage of an arc following dielectric breakdown GRM: n. (1,2,3) USG: sparkover is used when a disruptive discharge occurs in a gaseous or liquid dielectric, flashover is used when a disruptive discharge occurs over the surface of a solid dielectric in a gaseous or liquid medium, puncture is used when a disruptive discharge occurs through a solid dielectric References: SEEbreakdown SPEback flashover