Overvoltage categories
Electrical distribution systems and loads are becoming increasingly complex. This also results in the likelihood of transient overvoltage increasing. Power electronic modules in particular (e.g. frequency converters, phase angle and trailing-edge control, PWM-controlled power switches) generate temporary voltage peaks in conjunction with inductive loads, which can be significantly higher than the respective nominal voltage. In order to guarantee user safety, four overvoltage categories (CAT I to CAT IV) are defined in DIN VDE 0110 / EN 60664.
The measurement category indicates the permissible application ranges of measuring and test devices for electrical operating equipment and systems (e.g. voltage testers, multimeters, VDE test devices) for application in low voltage network areas.