Electrical Explosion: Understanding the Dangers and Protecting Workers

Electrical explosion is a term used to describe the violent release of energy caused by an electrical fault, typically involving an arc flash. In both the United States and Canada, these incidents pose serious risks to electrical workers across industrial, commercial, and institutional environments. An electrical explosion can produce extreme heat, blinding light, a powerful pressure wave, and shrapnel—all within milliseconds. Understanding the causes, effects, and prevention strategies is essential for electrical safety compliance under standards like NFPA 70E in the U.S. and CSA Z462 in Canada.

NFPA 70E Arc Flash Training

CSA Z462 Arc Flash Training

Request a Free Training Quotation

 

The Science Behind Electrical Explosions

An electrical explosion occurs when an electric arc forms between energized conductors or components, superheating the surrounding air and vaporizing metal. For example, copper can expand up to 67,000 times its solid volume when it vaporizes, creating a violent pressure wave. This sudden expansion generates a shockwave capable of damaging equipment, injuring personnel, and even causing fatalities.

Temperatures in an arc flash can reach 35,000°F—nearly four times hotter than the surface of the sun. These intense conditions can ignite clothing, melt equipment, and result in devastating thermal injuries. According to the Occupational Safety and Health Administration (OSHA), arc flash-related incidents are among the most dangerous hazards in electrical work environments.

 

Heat Radiation and Thermal Effects

The thermal radiation released during an electrical explosion can cause severe external and internal burns. Workers positioned up to 10 feet away may still receive dangerous levels of radiant heat, depending on the available fault current, the gap between conductors, and fault-clearing time. Even exposure to 200°F can result in irreversible skin damage, while superheated air and metal vapors can cause inhalation injuries to the lungs and airways.

In the U.S., the NFPA 70E standard emphasizes calculating "incident energy" to assess potential heat exposure and ensure appropriate electrical safety products are used.The Canadian equivalent, CSA Z462, uses similar methods to determine arc flash boundaries and appropriate PPE levels.

 

The Pressure Wave and Arc Blast

In addition to extreme heat, an electrical explosion produces a massive pressure wave known as an arc blast. The rapid expansion of superheated air and vaporized materials generates this blast. Pressure levels exceeding 2,000 pounds per square foot (psf) have been recorded near arc flash events, enough to collapse lungs, rupture eardrums, and knock workers off ladders or platforms.

The initial pressure peak typically occurs within the first half-cycle of the electrical fault—roughly 9 milliseconds after initiation. The concussive force can be compared to a small bomb detonating, which explains the term "explosion" in this context. Fragmented and molten metal may be propelled at speeds over 700 mph, creating secondary hazards such as lacerations and blunt trauma.

 

Toxic Smoke and Long-Term Health Risks

When an electrical explosion occurs, it often burns insulation, paint, and other synthetic materials. This produces a mixture of toxic gases, including hydrochloric acid, carbon monoxide, and dioxins. Inhaling these substances can lead to respiratory injuries or long-term illnesses. The risk is compounded when electrical rooms are inadequately ventilated or when explosions happen in enclosed spaces.

Both OSHA and the Canadian Centre for Occupational Health and Safety (CCOHS) warn of the long-term consequences of inhaling toxic byproducts from electrical explosions, which may include pulmonary damage or cancer risk from heavy metal exposure.

 

Frequency and Prevention in North America

In North America, it is estimated that five to ten electrical explosions occur every day in workplace settings. These events are often the result of maintenance errors, equipment failure, or insufficient arc flash hazard analysis — issues that can often be identified early using electrical safety testers. Despite ongoing efforts to improve awareness, many facilities still lack proper labeling, PPE usage, and arc flash training.

To address these issues, NFPA 70E and CSA Z462 both require employers to conduct periodic arc flash risk assessments, label electrical equipment with incident energy levels, and ensure workers receive comprehensive arc flash training.

 

Mitigating the Risk of Electrical Explosions

Electrical explosions are a severe and often underestimated threat to electrical workers across the USA and Canada. The combination of thermal energy, pressure, toxic exposure, and shrapnel makes these incidents highly dangerous. Fortunately, adherence to standards such as NFPA 70E and CSA Z462 and proper training and safety practices can significantly reduce the risk.

Organizations must invest in regular hazard assessments, provide up-to-date PPE, and educate workers on the mechanisms and dangers of electrical explosions. The stakes are too high for anything less. Utilizing appropriate Electrical Safety Products can mitigate explosion risks.