Read this article on reducing exposure in LV Distribution Systems as written by Maurice M’Mello, PE-Systems Engineer of GE Energy / Industrial Solutions / Canada.
Article conclusion: “….arc flash hazard analysis now tells us that the setting of protective devices on this basis could be detrimental to operational and maintenance personnel if an arcing fault occurs when the electrical equipment is worked on in the energized state. We must take into account the thermal limits of the human body (onset of second degree burns at 1.2cal/cm2 when selecting protective devices and their settings. Arc flash hazards are an extremely important consideration when designing electrical distribution systems.”
Click here to read the article distributed 4/5/12.