What Every Employee Should Know about Arc Flash

NFPA 70E—the standard for electrical safety in the workplace, is there to save lives and property. No doubt about it—arc flash is dangerous and potentially deadly.

Every workday in the United States, one person dies from electrocution, shock, arc blast or arc flash. Some 8,000 employees every year find themselves being treated in emergency rooms for electrical contact injuries.

What is an arc flash?

Usually air acts as an insulator, albeit a relatively poor one. Normally, electricity does not travel through the air in a normal business or industrial setting. Arc flash happens when the resistance of air to electrical current breaks down and electricity jumps the gap between conductors. This will only happen when there is sufficient voltage and a path to lower voltage or ground.

For example, an arc flash of roughly 1000 amperes can result in immense damage and potential fire and injury. At the arc terminals, temperatures can exceed 35,000 degrees Fahrenheit—about 25,000 degrees hotter than the surface (photosphere) of the sun. Not only does this melt adjacent metal, but right at the arc itself, metal vaporizes and becomes a superheated plasma, rushing outward with explosive force. Molten metal is blasted in every direction from the arc like shrapnel or liquid metal bullets.

More than the explosive forces involved, the radiation created by an arc flash can permanently blind those who look directly at it. The brutal ultraviolet radiation can leave permanent shadows on nearby walls and equipment—like a nuclear blast.

The operator closest to the equipment will likely be killed without adequate safety measures, but nearby people can be injured or killed also.

Improvements

New work practices in the updated standard help to reduce risks. This includes restrictions on cotton outerwear which might spontaneously combust under arc flash conditions. Recommendations are included for arc-resistant switchgear.

Recommendations

NFPA 70E training (arc flash training) is essential to understanding where such hazards may occur and how to comprehend and to navigate the new electrical code safety standards. Such corporate training could save lives and equipment not to mention eliminate the devastating effects on employee morale and public relations.

How can you acquire such training? Online training courses are available to bring all of the appropriate personnel up to speed on this critical safety issue. E-learning will allow them to take the training at their own pace and schedule so that disruption is minimized and safety goals are achieved more easily.

Image credit: Bram & Vera on Flickr