Arc Flash Overview

Five to 10 arc flash explosions occur in electrical equipment every day in the United States, according to statistics complied by CapSchell, Inc., a Chicago-based research and consulting firm that specializes in preventing workplace injuries and deaths. Injuries from arc flash events can be minor injuries to life threatening and possible death.

Arc Flash incidents typically occur in applications above 120V and can occur when electrical equipment is being serviced or inspected. In fact, some incidents occur when a worker is removing a cover or trim from a piece of equipment. Square D recommends that electrical equipment be de-energized before any applications and/or work is commenced.

An arc flash is caused by a reduction of the insulation or isolation distance between energized components. This could be caused by a tool being inserted or dropped into a breaker or service area, or other elements that may be accidentally left behind that could compromise the distance between energized components. Often incidents occur when a worker mistakenly fails to insure that the equipment has been properly de-energized.

An arc flash event can cause serious equipment damage and render the equipment no longer usable causing a disruption of a facilities operation for hours or days depending upon the equipment, its age and how quickly service can be restored. The explosion can also bend and distort pieces of the equipment leaving it unsuitable for service.

Square D, being a safety focused company has spent, the last several years designing and evaluating our high amperage circuit breakers from 600A to 6000A. Breakthrough technology, eliminating the use of fuse protected circuit breakers, was used in the design of our new Masterpact LF/ L1F “power” circuit breakers to act quickly during arc flash events to limit the arc flash incident energy providing protection to workers inside the arc flash boundary.