Contamination level

Insulation distance is one of the important factors that determine creepage distance and clearance distance. In IEC standards, pollution degree is classified into the following four levels.

Pollution Degree 1: Environments with clean air, such as clean rooms.
Pollution Degree 2: Environments such as inside control panels, and for electrical equipment, home appliances, and office equipment.
Pollution Degree 3: Environments such as general factories.
Pollution Degree 4: Outdoor environments.

As the pollution degree increases, the risk of dielectric breakdown and short circuits due to dust and condensation caused by humidity increases, so it is necessary to increase the insulation distance.