The insulation monitor RN 5897/020 of the VARIMETER IMD family is used especially for DC charging stations according to the IEC/EN 61851-23:2014/AC:2016-06 standard and monitors the charging process from the charging station into the vehicle. The device is characterised by the short response delay of ≤ 1s, a rated voltage up to DC 1000 V with coupling device and the detection of asymmetrical as well as symmetrical insulation faults.