electricarc

An electric arc, or arc discharge, is a continuous electrical discharge that forms between two electrodes in a gaseous medium when the applied voltage exceeds the breakdown threshold of the medium. The resulting plasma channel conducts current at high density and emits intense light, heat, and electrically induced radiation. Electric arcs can self-sustain for short or long durations, depending on voltage, current, and circuit conditions.

When the field ionizes the gas, free electrons and ions create a lower resistance path, allowing a stable arc to be maintained. The arc temperature is extremely high, typically several thousand degrees Celsius, sufficient to melt and vaporize metals. The arc column provides conductive plasma; electrode materials erode over time due to heat, chemical reactions, and sputtering. Magnetic and gas shielding influences arc shape and stability.

Electric arcs are central to metalworking and metal processing. Shielded metal arc welding uses a consumable electrode and a flux to protect the weld pool; other processes include gas tungsten arc welding and gas metal arc welding, which use inert or active shielding gases. Arcs are also used in lighting, such as carbon arc lamps historically and various modern arc lamps for specialized illumination, and in electric furnaces for steelmaking.

Arcs pose hazards, including electric shock, burns, ultraviolet and infrared radiation, ozone and nitrogen oxides, and fire risk. Safe operation requires appropriate electrical insulation, ventilation, protective equipment, and adherence to electrical standards. In electrical engineering, unintended arcing can indicate insulation failure and may cause equipment damage or fire.