Although not the most prevalent, arc flash injuries can be far more gruesome and painful than other electrical hazards. Arc flash is the light and heat produced from electrical energy that can cause substantial damage, harm, fire, injury or death.
Arc flash occurs when a flashover of electric current leaves its intended path and travels through the air from one conductor to another or to the ground. It can be caused by many things including dust, dropping tools, accidental touching, condensation, material failure, corrosion and faulty installation.
The severity of an arc flash is qualified in terms of incident energy, which is dependent on many factors such as short circuit current, arc duration and distance from the arc. Three factors determine the severity of an arc flash injury: proximity to the hazard, temperature and duration for the circuit to break.
As a result, the National Fire Protection Association has developed specific approach boundaries that define distances where specific hazards may exist. Of course, workers should wear personal protective equipment in accordance with NFPA 70E. These boundaries include the following:
Arc flash boundary: “When an arc flash hazard exists, an approach limit from an arc source at which incident energy equals 1.2 cal/cm2 (5 J/cm2).”
Limited approach boundary: “An approach limit at a distance from an exposed energized electrical conductor or circuit part within which a shock hazard exists.”
Restricted approach boundary: “An approach limit at a distance from an exposed energized electrical conductor or circuit part within which there is an increased likelihood of electric shock, due to electrical arc-over combined with inadvertent movement.”
The hazards within these boundaries are significant. An arc can generate heat as high as 35,000°F and a significant pressure wave blast. This can result in severe burns, destroying skin and tissue. It can ignite or melt clothing, resulting in further burns. Victims often require skin grafts or amputations. Death is more likely with increased severity of burns, percentage of body area affected and age.
The blast can even throw victims great distances, resulting in broken bones, concussions and internal injuries. Hearing loss can also result. The noise levels created from blasts have been measured at up to 141 decibels at 2 feet from the source. The intense heat may melt metal electrical components and blast molten droplets considerable distances as well. These droplets harden rapidly and can lodge in a person’s skin, ignite clothing or cause lung damage.
If an arc flash occurs and the victim is still in contact with the source of electricity, do not touch the person. Shut off the power and contact emergency personnel immediately. In the event the electricity cannot be turned off, use nonconductive materials and attempt to remove the victim from the electrical source. However, rescue and response should only be conducted if individuals have been properly trained to do so. In the event an arc flash victim is on fire, the flames can be smothered or doused. Do not attempt to remove clothing that is melted to the skin.
Never tell a conscious victim to move, as neck or spine injuries may have occurred as well. Attempting to move them could make injuries more severe. Check to see if they are breathing and if they have a pulse. If the victim is not breathing or does not have a pulse, you may need to begin CPR. Never perform artificial respiration on a victim that is breathing.
Run cool, not cold, water over the burn. Never apply creams, ointments or ice. Once a burn has been cooled, it can be covered with a clean dry cloth.
Avoid giving a victim food or water. Even if the victim feels fine, they should still seek medical attention. Certain effects of arc flash and electricity are not always immediately apparent.
According to the State of Washington’s Arc Flash/Blast fact sheet regarding the aftermath of an arc flash, “Physically, victims may suffer from chronic pain and scarring. Workers may also have difficulty reintegrating into the community, and may experience anxiety, depression, or other psychological symptoms. The social and economic costs may also be high. Workers’ compensation pays only a portion of lost wages. Some workers may not be able to return to their pre-injury job. Employers bear the costs associated with lost productivity, reduced competitiveness, employee rehiring and retraining, as well being subject to increases in workers’ compensation premiums.”