An arc flash blast is an explosive electrical arc that is powered with enough energy to cause fire, injury, death, or property damage, resulting from the insulation failure or accidental short-circuiting of an electric current between the air and uncontrolled conduction between ground, and different phases in an electrical system. These flashes can exceed temperatures of over 30,000 degrees Fahrenheit at the faults in their terminals, and vaporizes the metal and even ionizes the air within its circuit path, creating super-heated and expanding lava-like plasma that can move at high speed and force.
Normally, an arc flash does no major damage because high voltage fuses will open the circuit and eliminate electrical current, but any number of factors can create a potential for destruction and even death, if people are near the explosion. In some cases, the fuses in some instances cannot physically blow fast enough to completely isolate all electrical current from the short circuit, and the copper conductors in the bus bars will change from solid to plasma in an instant—but their conductive properties don’t change until the plasma has completely dissipated from the area.
This essentially creates an area of air that can conduct the electrical current that is now free to follow the path of least resistance. Obviously, since that path is so open and vague, the electrical current creates an arc that is represented by an explosive fireball cloud that can reach temperatures four times the temperature of the sun, and creating shrapnel and shock waves that can blow a person off of their feet and burn their skin, blind their eyes, potentially cause severe neural damage, or even death if they aren’t properly protected with the appropriately rated arc flash personal protective equipment (PPE).