Electric arc flash is one of the most serious and least understood electrical hazards. An electric arc (sometimes referred to as “electrical flashover”) is a continuous electric discharge of high current which flows through an air gap between conductors. This generates a very bright ultra-violet light as well as intensive heat. An arc flash is typically caused by a short circuit. This is sometimes due to a technical failure of electrical equipment (e.g. improper installation, dust, corrosion, surface impurities and sometimes simply due to normal wear and tear). However, in the majority of cases, short circuits are the result of a human error (e.g. caused by a worker touching a test probe to the wrong surface or from a slipped tool).
WHAT ARE THE CONSEQUENCES OF ELECTRIC ARC FLASH?
Depending on the severity of the arc flash, a function of arc current and the duration of the arc, and dependant on the distance from the arc, it can lead to:
The consequences for people working on or close to energized electric equipment will primarily depend on the amount of Incident Energy received at the body surface, which depends on its distance from the arc. The primary concern for the exposed person is skin burns.
WHEN DOES ELECTRIC ARC FLASH OCCUR?
Electric arc flash can occur whenever and wherever electrical equipment is live. During maintenance or repair, if for any reason the equipment cannot be made “dead”, then an electric arc can occur.