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Electric-Arc Flash Hazards

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Even 120/208V can create arcs with more than enough energy to burn exposed skin, ignite flammable clothing and cause catastrophic or fatal injuries. Low voltage does NOT justify energized work and requires appropriate arc flash gear.

Low voltage is not low risk. Arc flash incident energy depends mostly on amperage, cycle time, and worker distance, NOT voltage.

According to OSHA’s 29 CFR 1910.333 standard, “Conductors and parts of electric equipment that have been deenergized but have not been locked out or tagged ... shall be treated as energized parts.” All steps of lockout/tagout must be followed, or work does not qualify as deenergized and requires appropriate arc flash gear.

Wearing meltable or flammable undergarments is dangerous and prohibited under 29 CFR 1910.269. Even when the outer layer is arc-rated, some undergarments can melt or ignite easily when an electric arc occurs. Additionally, undergarments can melt or catch fire if the outer arc flash gear is worn incorrectly, such as with an untucked shirt, rolled-up sleeves, or unbuttoned clothing. Always wear PPE correctly to stay safe.

An electric arc is a type of electrical explosion. The electric arc produces a bright flash of hot gas, where temperatures can exceed 35,000 °F (19,400 °C), nearly four times the heat of the sun’s surface. The energy released in the arc rapidly heats and vaporizes the metal conducting the electricity, producing an explosive arc blast resulting in deafening noises, supersonic concussive forces, and super-heated shrapnel.

Most arc flash burn injuries are a result of the arc igniting flammable clothing and not from the arc itself.

Flammable Clothing vs Appropriate Arc Rated PPE (AR PPE)

Screenshot of video: Arc Flashes vs PPE: Why Proper Gear Matters

Special thanks to KEMA Laboratories and the Partnership for Electrical Safety for this testing footage

OSHA has produced the following guides to assist employers and employees in understanding and protecting against arc flash hazards:

For Employers

Screenshot of Protecting Employees from Electric Arc Flash Hazards

For Employees

Screenshot of Being Aware of Arc Flash Hazards

Screenshot of Common Electrical Work Myths

Screenshot of Establishing Boundaries Around Arc Flash Hazards

Additional Resources

  • NFPA 70E. NFPA 70E requirements for safe work practices to protect personnel by reducing exposure to major electrical hazards. Originally developed at OSHA's request, NFPA 70E helps companies and employees avoid workplace injuries and fatalities due to shock, electrocution, arc flash, and arc blast, and assists in complying with OSHA 1910 Subpart S and OSHA 1926 Subpart K. (viewable for free with NFPA account registration)
  • Partnership for Electrical Safety. The Partnership for Electrical Safety (PES) believes that every American working on or near energized electrical equipment deserves equal protection from arc flash, including the appropriate arc rated clothing and associated personal protective equipment (PPE). PES seeks to educate those at risk and to make plain to relevant oversight entities the need for use of PPE when doing industrial electrical work, and the extreme human and financial costs of non-compliance.