Severity Factors

The severity of an arc flash is qualified in terms of incident energy, which is dependent on factors including arc duration, short circuit current, and distance from the arc. The conditions that produce an arc flash determine the severity of injuries it may cause. Some of the factors that determine the severity of arc flash injuries are as follows:

Proximity to the event - Workers who are closer to an arc flash are more likely to sustain injuries from the explosion, electrical current, and other hazardous conditions caused by the blast. The level of PPE needed depends on the required proximity to hazardous equipment. Protective equipment will be explained in detail later in this course.

Available current - The magnitude of the explosion and the amount of electricity moving through the air during an arc flash depend upon the available current at the time of the event. Safety precautions involve calculating this factor to determine the level of risk presented by a piece of equipment.

Length of time before circuit breaks - An arc flash should trigger a safety mechanism to interrupt the circuit, stopping the event. The length of time it takes for a breaker or fuse to interrupt the circuit can determine the duration of the arc.

To learn more about Arc Flash Safety visit our OSHA Construction Arc Flash Safety Online Training web page.