Full definition
A sudden release of electrical energy through the air (arc) between conductors or from a conductor to ground, producing extreme heat (up to 20,000°C — 4x the surface temperature of the sun), intense light, pressure waves (up to 2,000 lb/ft²), molten metal, and toxic gases. Arc flash incidents cause severe burns, blindness, hearing loss, and fatalities. Per IEEE 1584 (arc flash hazard calculation), every electrical panel and switchgear must have an arc flash label specifying the incident energy level (cal/cm²) and required PPE category. NFPA 70E defines PPE categories: Category 1 (4 cal/cm², arc-rated clothing), Category 2 (8 cal/cm²), Category 3 (25 cal/cm²), and Category 4 (40 cal/cm², full arc flash suit). An arc flash risk assessment per NFPA 70E is mandatory before any work on or near energized electrical equipment. Mitigation: de-energize and LOTO whenever possible (the safest approach), install arc-resistant switchgear, use current-limiting fuses, reduce clearing times, and maintain safe approach boundaries. In Mexico, NOM-029-STPS covers electrical safety in workplaces. Rubber products used: dielectric mats (ASTM D178) and dielectric gloves (ASTM D120) as part of the electrical safety PPE system.