An arc flash is the energy release that occurs during an electrical fault when current flows through the air between two live conductors, causing a short circuit. In a residential setting, an arc flash usually produces little more than a brief flash of light before extinguishing itself harmlessly. In a commercial or industrial setting, however, voltages and currents are significantly higher, so electrical faults typically release far more energy. As a result, an arc flash routinely produces a powerful explosion marked by searing heat, toxic fumes, blinding light, deafening noise and massive pressure waves.
Temperatures can reach 35,000°F – more than three times hotter than the sun! These excessive temperatures cause the air and metal in the path of the arc to expand and explode, creating an arc blast.
Did you know that employers are required by law to estimate incident heat energy of electric-arc hazards and provide exposed workers the right personal protective equipment (PPE)?
Non-compliance with OSHA’s OSH Act exposes employees to serious safety threats and may result in hefty OSHA fines and even imprisonment for employers.
The National Electric Code (NEC) section methods for arc energy reduction, and the devices covered, include not only circuit breaker devices (Section 240.87) but also fusible devices (240.67). Learn more about each approved method to reduce arc energy, how to select a mitigation solution and comply with the NEC.