Insulation testing
What is insulation resistance testing?
Insulation resistance testing—also called an insulation resistance check—is a fundamental procedure in electrical test engineering and test & measurement technology. It determines the insulation resistance between conductive parts and protective insulation. A defined test voltage—depending on the standard from a few hundred volts up to several kilovolts—is applied, and the resulting resistance is measured in MΩ to GΩ.
The measurement provides insight into the operational condition and safety of cables, transformers, motors, power electronics, and photovoltaic systems. It helps detect insulation faults, moisture ingress, or material aging at an early stage.
Insulation resistance testing is required by many international standards (e.g., IEC, VDE, EN) and is used to demonstrate electrical operational safety and to support quality assurance in development and production.