Electrical arcs can develop when a gas is exposed to a voltage that is greater than the gas' insulating capacity. An arc will occur when the voltage is high enough to ionize the space between the conductors. Ionized air improves as a conductor, allowing electricity to move through it. Ionization of the air results in a current that generates heat and bright light. The phenomena got its name from the way this heat causes the ionized air to rise and form an arch-shaped current. The temperature that an arc flash may reach is 20,000 degrees Celsius. 

When a gas is exposed to a voltage greater than its insulating capabilities, electrical arcs result. The arc begins when the voltage is high enough to ionize the space between the conductors. A gas becomes a great conductor when it is ionized, allowing current to flow and producing the arc-shaped current known as an arc flash. Unintentional electrical discharge that results in a fire is known as an arc fault.