“Simply put, an arc flash is a phenomenon where a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to ground. The results are often violent and when a human is in close proximity to the arc flash, serious injury and even death can occur.”
—Workplace Safety Awareness Council (WPSAC)
What Causes an Arc Flash?
Arc flash incidents occur when electrical equipment is being serviced or inspected. The most common causes of arc‐flash incidents are:
Reduced insulation or isolation distance between energized components, which can be caused by material failure, corrosion, or faulty installation
Improper equipment operation, such as dropped tools, accidental touching, improper cleaning (dust or condensation).
Lack of proper maintenance, tools inserted or dropped into a breaker or service area, or conductive items accidentally left behind can all compromise the distance between energized components. The greatest danger is a worker who is unaware of the hazard and fails to properly de‐energize equipment.
Consequences of an Arc Flash
According to WPSAC, injuries and damage can be caused by burns, fire, flying objects, blast pressure (2000 lbs/sq foot or more), sound blast of up to 140 dB, and heat (35,000°F+).
Consequences of an arc flash are severe for employers and employees alike:
Average medical cost for a single arc-flash incident is over $1.2 million
Other damages or court costs
Ablated and eroded walls
Equipment bent and distorted
Equipment completely destroyed
Buildings damaged or rendered unsafe
Preventing Injury from an Arc Flash Incident
Perform an Arc Flash Hazard Assessment and Label Equipment. A knowledgeable Power Systems Engineer conducts an arc-flash study to:
Identify the level of hazard for each electrical component
Make recommendations regarding equipment and protective device settings
Provide warning labels showing the hazard and the appropriate Personal Protective Equipment required.
Training and awareness: All personnel who are exposed to electrical equipment and potentially hazardous situations must be trained and aware of all known hazards.
Proper equipment maintenance: Equipment malfunctions are a common cause of arc flash incidents. Equipment should be regularly serviced and maintained to reduce the chance of an arc‐fault incident.
Occupational Safety and Health Administration(OSHA)