The unwanted flow of electrical current across the surface of an insulating material, rather than through the air. It usually happens when dust, salt spray, or moisture builds up on the insulator, compromising its dielectric strength and providing a conductive path to ground.
Heard on the job
We had an arcover on the 132 kV bushing because of heavy salt pollution from the coastal storm.
Also heard as
- flashover
- tracking
Do not mix it up with
- Flashover: Arcover specifically implies the arc traveling over a physical surface, whereas flashover can happen directly through the air gap.
Related terms
Flashover
Disruptive discharge over or around insulation that creates a short circuit through the air.
Creepage distance
Shortest route over an insulating surface from one conductive part to another, the dimension that resists tracking.
Insulation
A material with high electrical resistance used to isolate conductors and prevent current leakage.