ČSN EN IEC 60974-1 ed. 6 - Zařízení pro obloukové svařování - Část 1: Zdroje svařovacího proudu

3.1.41 pollution degree 

numeral characterizing the expected pollution of the micro-environment   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 4.5.2 of IEC 60664-1:2020.  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: Continuous conductivity occurs due to conductive dust, rain or other wet conditions.  [SOURCE: IEC 60050-581:2008, 581-21-07, modified – Modification of the Note to entry.]