Pollution degree classifies the micro-environment around insulation. Degree 1 is sealed or clean with no pollution, degree 2 is normal indoor with occasional condensation, degree 3 is industrial with conductive dust or frequent condensation, and degree 4 means the surface stays conductive for long stretches, as outdoors in rain or snow. Required creepage distances climb steeply with each step, so choosing the right degree early decides enclosure sealing and board layout.
That control panel lives in a cement plant, design to pollution degree 3 or the creepage on those terminals won't last.
Also heard as
- PD
Related terms
Creepage distance
Shortest route over an insulating surface from one conductive part to another, the dimension that resists tracking.
CTI
Comparative tracking index: voltage an insulating material withstands before tracking under a wet contamination test.
Tracking
Conductive carbon trail that leakage arcs through dirt and moisture gradually burn across an insulating surface.