A Flashover or an arcing fault occurs when current flows between two conductors or between the conductor and the ground or a neutral line. A sudden burst of Energy is released during an arcing fault.

The high current which flows during a flash over can cause a sudden blast of energy in the form of heat, light and sound.

Personnel who come in contact with the arc or are in the vicinity of the fault can face serious injuries such as burns, damage to sight and hearing. Sometimes, Flashovers can lead to death of personnel. The Flashover is usually accompanied by a tremendous pressure blast which may throw pieces of equipment (shrapnel) over large distances increasing the chance of injury to people nearby

Flashovers can be caused by a number of reasons such as making contact with energized equipment accidentally, dropping tools into energized equipment such as busbars, transformers when working on them. The accumulation of dirt, dust and moisture over extended periods of time can also trigger flashovers in equipment.

Flashovers can be prevented by following standard safety procedures while working on Energized equipment. Routine safety drills will also greatly reduce mistakes during work. It must be ensured that all HV equipment are insulated. The minimum line-to-line and line-to-ground clearances should be followed for all busbars. The Insulation Resistances of all cables and windings need to be checked at scheduled intervals

The relays and other protective devices should be periodically checked for correct operation.