The Definition of Arc Flash

Definition of Arc Flash

An arc flash is a sudden and violent release of energy caused by an electrical arc fault, occurring when electrical current travels through the air between conductors or from a conductor to ground, generating intense heat, a powerful pressure wave, and often a shower of molten metal. Arc flash incidents can cause severe burns, hearing damage, and other traumatic injuries within a fraction of a second, making it one of the most serious hazards associated with working on or near energized electrical equipment. Arc flash risk is typically assessed through an arc flash hazard analysis, which determines the incident energy at a given point in an electrical system and informs the required level of PPE and safe working boundaries.

Example of Arc Flash

An electrician performing maintenance on an energized electrical panel wears arc-rated flame-resistant clothing and a face shield rated for the panel's calculated incident energy level, as determined by the facility's arc flash hazard analysis, before beginning work.

Frequently Asked Questions: Arc Flash

What causes an arc flash to occur?

Arc flash incidents are typically caused by equipment failure, accidental contact between conductors, dropped tools, dust or corrosion buildup, or human error during work on energized electrical equipment, any of which can create a path for current to arc through the air rather than through its intended conductive path.

What is an arc flash hazard analysis?

An arc flash hazard analysis is a formal engineering study that calculates the potential incident energy at specific points within an electrical system, used to determine the appropriate arc flash boundary and the required level of PPE for workers performing tasks on or near that equipment.

What PPE is typically required for arc flash protection?

Required PPE varies based on the calculated incident energy level but commonly includes arc-rated flame-resistant clothing, face shields or arc-rated hoods, insulated gloves, and hearing protection, with higher incident energy levels requiring higher-rated protective gear.