A dangerous condition where electric current flows through an air gap between two conductors or a conductor and ground. This creates intense localized heat that can start fires or degrade equipment, often caused by damaged insulation, loose connections, or foreign objects bridging a gap.
Heard on the job
The relay detected an intermittent arc fault on the feeder before it escalated into a bolted short.
Also heard as
- arcing fault
Related terms
Arc flash
Explosive release of heat, light and pressure when an electric arc forms through air between energised parts.
Flashover
Disruptive discharge over or around insulation that creates a short circuit through the air.
Clearance
Straight-line air gap between two conductive parts, the dimension that decides whether a surge can flash across.