ČSN EN 60974-1 ed. 4 - Zařízení pro obloukové svařování – Část 1: Zdroje svařovacího proudu

3.40 pollution degree

numeral characterizing the expected pollution of the micro-environment [SOURCE: IEC 60664-1:2007, 3.13] Note 1 to entry  For the purpose of evaluating creepage distances and clearances, the following four pollution degrees in the micro-environment are established in 4.6.2 of IEC 60664-1:2007. a) Pollution degree 1: No pollution or only dry, non-conductive pollution occurs. The pollution has no influence. b) Pollution degree 2: Only non-conductive pollution occurs except that occasionally a temporary conductivity caused by condensation is to be expected. c) Pollution degree 3: Conductive pollution occurs, or dry, non-conductive pollution occurs which becomes conductive due to condensation which is to be expected. d) Pollution degree 4: The pollution generates persistent conductivity caused by conductive dust or by rain or snow.