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Arc Flash Boundary Infographic Outlines Safety Requirements Set By NFPA 70E Standards

Know your limits. One step too close to an energized piece of equipment may cause burns that char deep into your flesh and blisters that reach beyond the second layer of your skin. In the event of an arc flash, personal protective equipment (PPE) is your last line of defense. But knowing your boundary limits just might save your skin.

Graphic Products has published an Arc Flash Boundary Infographic, which outlines the three safety boundaries around electrical equipment, as developed by The National Fire Protection Association (NFPA). NFPA developed these boundaries in an effort to protect employees from the hazards of arc flash and electric shock while working on or near energized equipment.


“Distance is the simplest form of protection from electrical injuries,” said Jeff Woods, Safety Auditor with Graphic Products. “These safety boundaries give workers a ‘stay-back’ distance that they can easily and quickly understand, keeping them out of harm’s way.”

The flash protection boundary is an imaginary sphere that surrounds equipment at which an unprotected person would probably receive a second-degree burn in the event of an arc flash. Any closer, and workers are at risk of very serious injuries, while staying farther away will restrict injuries to first-degree, curable levels. But calculating the arc flash boundary is complex, partly because the phenomenon of arc flash is still being researched.

The NFPA Standard for Electrical Safety in the Workplace, or NFPA 70E, doesn't specify how the arc flash boundary must be calculated; although several different formulas for arc flash calculations exist. These calculations are paramount when creating arc flash labels. According to the 2015 edition of the standard, arc flash labels must not only include information such as nominal system voltage and PPE requirements, but also include the arc flash boundary.

“Anyone who needs to work near live equipment should understand where the ‘danger zone’ is,” Wood said. “That’s why clear labeling is important.”

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