Degree of pollution (electrical engineering)
The degree of pollution in electrical engineering is a parameter for dimensioning the air and creepage distances in electrical equipment .
Clearances are dimensioned according to the overvoltages to be expected, taking into account the rated values of the overvoltage protection device used and the expected environmental conditions, taking into account the protective measures taken against pollution. Creepage distances are measured according to the operating voltage, taking into account the environmental conditions to be expected, taking into account the protective measures taken against contamination and the insulating materials used.
The dimensioning of the clearances is determined by the rated impulse voltages resulting from the overvoltage category , the network configuration ( TT , TN or IT system ) and the nominal line voltage derived from conductor-earth. The minimum clearances are determined from the rated impulse voltage and the degree of pollution.
The degree of pollution is differentiated in the IEC 61010-1 standard according to the following four categories:
- Pollution degree 1 allows little or no, but non-conductive pollution. The pollution has no influence.
- Pollution degree 2 is non-conductive pollution that can become conductive due to occasional condensation or hand sweat .
- Pollution degree 3 is pollution that is conductive or becomes conductive through condensation.
- Pollution degree 4 : There is permanent conductivity caused by conductive dust, rain or moisture.
Norms
DIN EN 61010 -1 Safety requirements for electrical equipment for measurement, control and laboratory use , Part 1: General requirements - (IEC 61010-1: 2010 + Cor.:2011); German version EN 61010-1: 2010
Web links
- International Electrotechnical Dictionary - IEV 851-15-17