An arc flash is a complex phenomenon gaining increased awareness and attention in the electrical safety industry. An arc flash is ionized gas caused when electricity travels through air. The primary dangers of an arc flash are thermal, copper vapors, and intense light. Electrical Safety Specialists are the leaders in their industry with providing protection against arc flashes and more.
When an electric current passes through air between ungrounded conductors or between ungrounded conductors and grounded components, the temperatures can reach 35,000°F. Exposure to these extreme temperatures both burns the skin directly and causes ignition of clothing, which adds to the burn injury. The majority of hospital admissions due to electrical accidents are from arc flash burns, not from shocks. Each year more than 2000 people are admitted to burn centers with severe arc flash burns. Arc flashes can and do kill at distances of 10 feet.
An arc blast is very dangerous. The tremendous temperatures of the arc cause the explosive expansion of both the surrounding air and the metal in the arc path. For example, copper expands by a factor of 67,000 times when it turns from a solid to a vapor. The danger associated with this expansion is one of high pressures, heat, sound, and shrapnel. The high pressures can easily exceed hundreds or even thousands of pounds per square foot, knocking workers off ladders, rupturing eardrums, and collapsing lungs.
Electrical equipment such as switchboards, panel-boards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units, and are likely to require examination, adjustment, servicing, or maintenance while energized.
Arc flash protection is very important. Electrical equipment, such as switchboards, panel-boards, industrial control panels, meter socket enclosures, and motor control centers, in other than dwelling occupancies, that are likely to require examination, adjustment, servicing, or maintenance while energized, shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment.