An arc flash is the rapid release of undesired energy primarily from an electrical arcing fault. This hazardous incident happens faster than a blink of an eye and causes devastating consequences.
Arc flash is a dangerous instantaneous electrical event that occurs often. Electrical workers face many hazards on a regular basis. In fact, working with or near electricity presents the risk of electrical events, which can severely injure or even kill workers.
According to the National Institute for Occupational Safety and Health (NIOSH), five to 10 arc flash incidents occur each day in the U.S. Arc flash is extremely dangerous because it can produce some of the highest temperatures known to occur on earth, up to 35,000 degrees Fahrenheit, which is four times the temperature of the surface of the sun!
The Occupational Safety and Health Administration (OSHA) defines arc flash as “a phenomenon where a flash-over of electric current leaves its intended path and travels through the air from one conductor to another, or to ground.” According to a study conducted for NIOSH, arc flash can be spontaneous or result from inadvertently bridging electrical contacts with a conducting object. They can also be caused by many factors including:
Less visible reasons why an arc flash can occur:
- Excessive dust
- Accidental contact
- Corrosion on poorly maintained equipment
- Insulation gaps that cause sparking
Any worker whose job duties might include opening of electrical cabinets or circuit breaker panels is at risk of injury. An arc flash can carry across large spaces, anyone who works near electrical equipment and cabinets is also a potential victim.
The common causes of arc flash are negligence (human error) and equipment failure. For instance, poorly maintained equipment or breakdown of insulation can cause an arc flash. Typical results from an arc flash include:
- Burns: An arc flash may produce temperatures exceeding 35,000 degrees Fahrenheit. Although the arc fault that causes flashes tends to burn away quickly, the energy it discharges may burn everything in its path.
- Pressure Waves: Upwards of 2,000 pounds per square foot. The force of an arc flash explosion can easily knock off even the sturdiest employee off their feet.
- Intense Light: An arc flash will produce intense light that may damage your employees’ eyesight including blindness.
- Sound Waves: An arc flash produces sound that can reach 140 decibels that can cause damage and hearing loss.
- Toxic Fumes: An arc flash can create poisonous gases. If inhaled, these gases can cause lung damage.
The safest way to prevent accidental injury or even death is to de-energize the equipment that is being repaired, maintained, inspected or serviced.