Arc flash is a short circuit through air that flashes over from one exposed live conductor to another conductor or to ground. Arc flash incidents are common and costly, and the frequency of reported accidents is increasing – making arc flash a very hot topic within OSHA and the overall safety industry.
What Causes Arc Flash? Arc flashes can be caused in a variety of ways:
• Just coming close to a high-amp source with a conductive object can cause the electricity to flash over.
• Dropping a tool or otherwise creating a spark can ignite an arc flash.
• Equipment failure due to use of substandard parts, improper installation, or even normal wear and tear.
• Breaks or gaps in insulation.
• Dust, corrosion or other impurities on the surface of the conductor.
How Common Is Arc Flash? In the past, if someone suffered burns in an electrical accident, people thought the burns were caused by the electrical shock passing through the body. Electrical shocks can cause burns. But what research has shown is that most burns from electrical accidents actually come from arc flash.
According to the NFPA 70E-2004 standard, the majority of hospital admissions due to electrical accidents are from arc flash burns, not from electrical shocks. Of the approximately 350 persons killed in the work place by electricity last year, roughly 50% were related to arc flash
A report compiled by Capelli-Schellpfeffer, Inc., estimates that five to 10 arc flash explosions happen in the USA every day, resulting in 1 to 2 deaths per day.
That figure only takes into account incidents where victims were sent to special burn centers. The number does not include cases sent to regular hospitals or clinics, nor unreported cases or near misses.
NFPA 70E-2012 states that each year more than 2000 people are admitted to burn centers with severe arc flash burns.