Electrical hazards: the invisible killer on job sites
Arc flash, shock, and electrocution prevention
Electrical hazards cause roughly 4,000 injuries and 1,000 deaths in U.S. workplaces every year. Arc flash can reach 35,000°F — hotter than the surface of the sun — while a shock you never see coming can stop the heart in an instant. OSHA Scan surfaces these hazards from a single photo so you can act before anyone gets hurt.
- Electrical hazards include contact with live circuits (shock and electrocution), arc flash (severe burns and eye damage), arc blast (pressure waves and flying debris), thermal burns from hot equipment, and fires from electrical faults. What makes them so dangerous is that they are invisible — a worker cannot see energized conductors, so the danger is constantly underestimated until the moment of contact.
- The severity of an electrical injury depends on the voltage, the duration of contact, the resistance of the body (wet skin dramatically lowers resistance), and the path the current takes — current across the chest and heart is the most lethal. Alternating current is generally more dangerous than direct current because it can cause muscles to clamp onto the source.
- Arc flash deserves special attention. It occurs when current jumps a gap in a circuit, releasing an enormous burst of heat, light, and pressure in a fraction of a second. Workers standing feet away can suffer third-degree burns, hearing loss, and blast injuries even without ever touching a live part.
What is arc flash?
An arc flash is a sudden release of electrical energy through the air when current jumps across a gap between conductors. It produces intense heat (up to 35,000°F), blinding light, and a pressure blast. Workers can suffer severe burns, hearing damage, and blast trauma even from several feet away, which is why arc flash boundaries and arc-rated PPE are critical.
When is lockout/tagout required?
Lockout/tagout is required any time a worker services or maintains equipment where unexpected energization could cause injury. Each authorized worker applies their own lock and tag, and only that worker may remove them. It is one of OSHA's most-cited standards precisely because skipping it is so often fatal.
Can I work on energized equipment?
OSHA expects circuits to be de-energized before work. Energized work is only permitted when de-energizing introduces a greater hazard or is infeasible, and it then requires an energized-work permit, an arc flash risk assessment, and appropriate arc-rated PPE and insulated tools.
What PPE do I need for electrical work?
It depends on the incident energy at the equipment. At minimum, expect voltage-rated insulated gloves, arc-rated clothing matched to the hazard category, safety glasses, and insulated tools. Inside the arc flash boundary you may also need a face shield or full arc flash hood.