Which of the following is true of an arc flash?
It could have a temperature exceeding 35,000°??
It occurs when a flashover of electric current leaves the intended path and travels through the air
In addition to burns, it can damage workers’ eyesight and hearing
All of the above
The correct answer and explanation is:
Correct Answer: All of the above
An arc flash is an explosive release of energy caused by an electrical fault. It is a serious hazard in workplaces involving electrical systems. Let’s examine each statement:
1. It could have a temperature exceeding 35,000°F
This is correct. An arc flash generates extreme heat, with temperatures exceeding 35,000°F (19,427°C). Such temperatures are hotter than the surface of the sun. This intense heat can vaporize metals, melt insulation, and cause severe burns to workers even at a distance. The heat also ignites flammable materials, increasing the risk of secondary fires.
2. It occurs when a flashover of electric current leaves the intended path and travels through the air
This is accurate. An arc flash happens when there is an electrical fault, such as a short circuit, causing electricity to travel through the air between conductors or between a conductor and the ground. It may result from human error, equipment failure, or dust and debris accumulating on electrical components. The unintended current path creates a highly energetic explosion.
3. In addition to burns, it can damage workers’ eyesight and hearing
This is true. Arc flashes produce intense light, including ultraviolet and infrared radiation, which can cause temporary or permanent vision damage. The sound generated by the explosion can exceed 140 decibels, leading to hearing loss or damage. The blast pressure can also cause other physical injuries, including lung damage and broken bones.
Summary
Arc flashes are among the most dangerous electrical hazards, posing risks of severe burns, trauma, and other injuries. Understanding and mitigating these risks through proper safety protocols, personal protective equipment (PPE), and training is crucial in workplaces. Implementing arc-flash hazard assessments and ensuring compliance with safety standards like NFPA 70E can significantly reduce these risks.