Arc Flash Hazards

Causes of Arc Flash

What Causes Arc Flash Hazards?

In short, electrical short circuits cause the arc flash hazards. Electrical faults on electrical systems can be in the form of phase-to-ground, double phase-to-ground, and three phase.

The amount of energy in an arc can be enormous in some cases. Electrical arcs create plasma, hot vapors, and gases that can rise to 23,000 °F. The heat produced can ignite clothing more than 10 feet away. The amount of burning is based upon the amount of Incident energy created by the fault.

The faults create intense thermal radiation and damaging noise levels. The explosive expansion of the surrounding air can create pressure waves that can blow personnel across rooms and up against walls. Arcing faults cause the vaporization of copper components. This copper vaporization is projected outward along with the Incident energy.

At this time, only arc flash hazards from three phase faults (arcing faults) in enclosures have been studied and researched. There is little test information on arc flash hazards produced by phase-to-phase and phase-to-ground faults. Arc flash hazards have not been studied for a bolted fault because it does not radiate any flash energy.