Arc Blast and 40 calories/centimeter squared

You look at the arc flash warning label and scratch your head. Danger! No PPE Category Found. No personal protective equipment (PPE) category? Now what? This type of language is often on arc flash warning labels when the calculated incident energy exceeds 40 calories per centimeter squared (cal/cm2). What is so special about the number 40?  The fear of the Arc Blast is not always well founded.

Download:  Arc Blast – 40 cal/cm^2