Pollution degree is a classification according to the amount of dry pollution and condensation present in the environment. This classification is important as it affects parameters required to ensure safe operation of the product. The categorization is as follows:

Pollution: Definition, Example

Pollution Degree 1 : No pollution or only dry non-conductive pollution. It has no effect. Clean room environments, Inside sealed components

Pollution Degree 2: Normally only non-conductive pollution. Temporary Condensation possible. Offices, laboratories, test stations

Pollution Degree 3: Conductive and non-conductive pollution present. Condensation frequent. Industrial & farming areas (under cover), unheated rooms, Boiler rooms

Pollution Degree 4: Pollution generates persistent conductivity caused by wet dust, rain or snow. Outdoor use, remote stations

Suitability of a device is assessed by examining the creepage and clearance distances which then determine how resilient the unit is to effects of pollution.

Definition

Clearance is the shortest distance in air between two conductive parts

Creepage is the shortest distance along the surface of the insulating material between two conductive parts.