An arc flash is a dangerous electrical situation where current races through the air, creating plasma and causing severe damage. It is explosive and may generate shrapnel, depending on what kind of material is present. There are some steps people can take to reduce the risk of creating an arc flash, and protective gear is available for workers in environments where it is more likely. Most electrical codes cover this safety issue and provide advice and recommendations on addressing it.
In an arc flash, current moving through an exposed electrical conductor takes a shortcut through the air to the ground or a conductor with lower voltage. Normally the air resists electrical currents, but when something goes wrong in an electrical system, it can create a short. The connection creates extremely hot plasma that will burn electrical equipment and cause an explosion, throwing materials around the area. Workers in the area can be seriously injured, and there may be structural damage.
Arc flash can happen because of insulation breakdowns, sparks, dropped tools, or activation of a high amperage circuit. Some basic safety procedures like keeping electrical conductors covered when people are not actively working on them, maintaining systems before they break down, and handling electricity with care can greatly reduce the risk of arc flash. It is also important to keep the area around electrical conductors clean, and to make sure warning signs are highly visible so people know to exercise caution.
Before people start work on a system they usually need to deenergize it, or get out gear suitable for working with energized electrical systems if they cannot shut the power off. They also wear protective gear to address the risk of arc flash and other hazardous conditions. Workplaces with dangerous electrical systems must have safety procedures in place for handling them, including indicators to let people know when other people are working on the system so they do not accidentally energize it and injure someone.
Electrical workers can receive arc flash training from safety organizations. Instructors may come to their workplaces to help them identify safety risks and address them, and they can attend training courses in school facilities. Electricians may also conduct audits of workplace environments to determine if they are up to code and make recommendations for addressing code violations or causes for concern. Even if a practice is not necessarily illegal, it may not be in alignment with the standards and practices of the industry, or could be a commonsense safety issue.