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ISOMETER® isoEV425 with AGH420

  • Insulation monitoring device for AC 690 V and DC 1000 V IT systems
  • Monitoring of DC charging stations for electric and hybrid vehicles
  • Settings in accordance with IEC 61851-23
  • Parameter settings by the customer not required

The ISOMETER® of the isoEV425 series monitor the insulation resistance of unearthed DC-charging stations for electric vehicles (IT systems) DC 0…1100 V DC from the charging station to the motor (AC 0…793 V).

Due to a separate supply voltage de-energised systems can also be monitored.


  • Monitoring for DC charging stations (mode 4 acc. to IEC 61851-23) for charging of electric vehicles
  • Measurement of the mains voltage (r.m.s.) with undervoltage and overvoltage detection
  • Measurement of DC voltages system to earth (L+/PE and L-/PE)
  • Automatic adaptation to the system leakage capacitance up to 5 μF or 20 μF
  • Automatic device self test with connection monitoring
  • Selectable start-up delay, response delay and delay on release
  • Two separately adjustable response value ranges of 1kΩ …500 kΩ (Alarm 1, Alarm 2)
  • Alarm signalling via LEDs (AL1, AL2), a display and alarm relays (K1, K2)
  • N/C operation or N/O operation of the relays selectable
  • Measured value indication via multifunctional LCD
  • Fault memory can be activated
  • RS-485 (galvanically isolated) including the following protocols:
    – BMS interface (Bender measuring device interface) for data exchange with other Bender components
    – Modbus RTU
    – IsoData (for continuous data output)
  • Password protection to prevent unauthorised parameter changes


  • DC charging stations for electric vehicles according to IEC 61851-23

ISOMETER® isoEV425 with AGH420 Variant(s)

TypeSupply voltage USSystem leakage capacitance CeArt. No.*
isoEV425-D4 with AGH420AC 100…240 V, 47…63 Hz / DC 24…240 V≤ 5 μFB71036401
isoEV425HC-D4 with AGH420AC 100…240 V, 47…63 Hz / DC 24…240 V≤ 20 μFB71036397

*(B7… = push-wire terminal / B9… = screw-type terminal)

Optional Accessories for ISOMETER® isoEV425 with AGH420

TypeArt. No.
Mounting clip for screw mounting (one piece per device)B98060008
Mounting frame XM420B990994 

Downloads for ISOMETER® isoEV425 with AGH420

Declarations of Conformity isoxx425 - UKCA 142.1 KB 2022/12/20 05:59:4420.12.2022 05:59:44
CE Declarations of conformity AGH 145.4 KB 2022/08/12 06:17:2512.08.2022 06:17:25
CE Declarations of conformity isoXX425 151.9 KB 2023/01/09 06:50:5109.01.2023 06:50:51
Quickstarts isoEV425 813.8 KB DE2019/08/09 09:03:3209.08.2019 09:03:32D00126
Quickstarts isoEV425 807.4 KB EN2019/08/09 09:03:3109.08.2019 09:03:31D00126
Manuals isoEV425 1.5 MB DE2019/05/13 10:31:4613.05.2019 10:31:46D00126
Manuals isoEV425 1.4 MB EN2021/01/22 06:14:1022.01.2021 06:14:10D00126
Datasheets isoEV425 390.9 KB DE2020/07/24 10:37:5124.07.2020 10:37:51D00126
Datasheets isoEV425 387.1 KB EN2020/07/24 10:37:5524.07.2020 10:37:55D00126
Datasheets isoEV425 377.9 KB ES2020/07/24 10:37:4624.07.2020 10:37:46D00126
Datasheets isoEV425 578.7 KB ZH2019/05/13 10:31:3313.05.2019 10:31:33D00126
Software Modbus RTU - Monitor isoxx425 V2.2.2 setup 7.1 MB 2019/05/13 10:31:5913.05.2019 10:31:59