An arc flash occurs when a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to neutral or ground. It often happens unexpectedly and can be explosive but brief, or it can last seconds and be rather visually spectacular. It can cause a little damage or it can disable a system and require the replacement of equipment. An arc flash of any size is quite dangerous because its path is unpredictable; it will be attracted to the nearest item with the greatest conductivity, such as an unsuspecting rodent or house pet, or a person. An arc flash can cause a serious electrical burn or even fatal electrocution. Photo courtesy of EHSToday.com
An arc flash can have various catalysts, including:
excess dust;
condensation;
corrosion;
component failure;
faulty system installation;
dropping a metal tool, which may cause even a small spark; and/or
accidental contact.