An arc flash is an undesired electric discharge that travels through the air between conductors or from a conductor to a ground. The resulting explosion can cause fires and serious harm to equipment and people.
The temperature of an arc flash may exceed 35,000 degrees Fahrenheit, which is capable of vaporizing metal and sending a blast of plasma and molten metal in all directions with extreme force. Generally, an electrical system must run at more than 480 V to supply an arc flash; the higher the voltage, the higher the risk. Damage is caused both by the explosion of the arc flash and by the heat radiating from the blast.
It is possible to protect against arc flash with the proper protective equipment and, more importantly, safety procedures and training. The IEEE has created a set arc flash standards that companies can use during facilities planning to help minimize the risk of arc flash in the first place.