The arc flash boundary is the minimum “safe” distance from exposed energized conductors or circuit parts that has the potential for an arc flash. Arc fault incidents happen daily in the United States.

Why is the arc flash boundary defined?

The Arc Flash Boundary determines the distance from the equipment at which the Incident Energy of an arc flash would be 1.2 cal/cm². The electrical worker has to be able to determine his relative risk, according to the distance from the equipment. The Arc Flash Boundary helps him to determine a safe distance.

What is the default arc flash boundary?

The default boundary extends 4 feet from the energized exposed components, and anytime an individual is inside this boundary they must wear proper PPE to avoid a permanent injury in the event of an arc-flash.

Simply put, the arc flash boundary is the distance at which an electrical arc can flash/expand outward, which may endanger employees working on electrical equipment. People that are not adequately protected must stay away from a potential arc flash source by this calculated minimum distance at all times.