An electric arc follows a short circuit. It produces nearly instant effects with serious consequences without proper protection.
When electric arc danger exists, heat-resistant clothing must be worn. The arc’s characteristics are given by: The resistance value of the free arc, expressed in cal/cm2 according to NFPA 70 E, ASTM standards, and IEC 61482-1-1. or The protection class (1 or 2) with a constrained arc according to IEC 61482-1-2.
PROTECTION AGAINST ARC FLASH
The following are used to determine the proper equipment for protecting against an electric arc.
The maximum fault current value.
The phase/ground rated voltage at the site of the risk.
The distance between the source of the arc and the reception surface.
The AC cycle number and the mono or three-phase circuit type.
The location where the arc is produced (confined space).
After recording these parameters, we can estimate the level of risk and determine
The proper protective clothing and PPE to use: 8 to 100 cal/cm2 or class 1 or 2.