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  • Monitoring the insulation resistance for DC charging stations according to Japanese charging standard CHAdeMO
  • Detection of asymmetrical insulation faults in the DC system voltage range between 50 V und 400 V within 1 s
  • Detection of symmetrical insulation faults within 10 s
  • Measurement of the system voltage (true RMS) with undervoltage and overvoltage detection
  • Measurement of DC system voltages to earth (L+/PE and L-/PE)

The ISOMETER® monitors the insulation resistance of DC charging stations according to the Japanese charging standard CHAdeMO for voltages between DC 50 V and 400 V.

Asymmetric insulation faults are reported with a response time ≤ 1 second. Symmetrical insulation faults within 10 seconds. The maximum permissible system leakage capacitance Ce is 2 μF.

In order to meet the requirements of applicable standards, customised parameter settings must be made on the equipment in order to adapt it to local equipment and operating conditions.

Please heed the limits of the range of application indicated in the technical data. Any use other than that described in this manual is regarded as improper.


  • Monitoring the insulation resistance RF for DC charging stations according to Japanese charging standard CHAdeMO
  • Detection of unipolar insulation faults in the nominal voltage range between 50 V und 400 V within 1 s
  • Detection of two-pole insulation faults within 10 s
  • Measurement of the nominal system voltage Un (true RMS) with undervoltage and overvoltage detection
  • Measurement of residual voltages UL+e (between UL+ and earth) and UL-e (between UL- and earth)
  • Automatic adaptation to the system leakage capacitance Ce up to 2 μF
  • Selectable start-up delay, response delay and delay on release
  • 2 separately adjustable response value ranges of 5…250 kΩ (Alarm 1, Alarm 2)
  • Alarm signalling via LEDs (AL1, AL2), a display and alarm relays (K1, K2)
  • Automatic device self test with connection monitoring
  • Selectable N/C or N/O relay operation
  • Measured value indication via multi-functional 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 the Japanese charging standard CHAdeMO

ISOMETER® isoCHA425 Variant(s)

TypeSupply voltage UsSystem leakage capacitance CeArt. No.
isoCHA425-D4-4AC 100…240 V, 47…63 Hz / DC 24…240 V≤ 2 μFB71036395

Optional Accessories for ISOMETER® isoCHA425

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

Downloads for ISOMETER® isoCHA425

Declarations of Conformity isoxx425 - UKCA 142.1 KB 2022/12/20 05:59:4420.12.2022 05:59:44
CE Declarations of conformity isoXX425 151.9 KB 2023/01/09 06:50:5109.01.2023 06:50:51
Manuals isoCHA425 2.4 MB DE2021/05/12 13:36:5312.05.2021 13:36:53D00352
Manuals isoCHA425 2.4 MB EN2021/05/12 13:36:5812.05.2021 13:36:58D00352
Quickstarts isoCHA425 1,014.3 KB DE2021/05/12 13:37:0512.05.2021 13:37:05D00352
Quickstarts isoCHA425 1,014.3 KB EN2021/05/12 13:37:0512.05.2021 13:37:05D00352
Datasheets isoCHA425 418.5 KB DE2021/07/28 07:30:2328.07.2021 07:30:23D00352
Datasheets isoCHA425 413.9 KB EN2021/07/28 07:30:2828.07.2021 07:30:28D00352
Software Modbus RTU - Monitor isoxx425 V2.2.2 setup 7.1 MB 2019/05/13 10:31:5913.05.2019 10:31:59
Datasheets isoCHA425 417.1 KB FR2021/07/28 07:30:3828.07.2021 07:30:38D00352
Datasheets isoCHA425 418.0 KB ES2021/07/28 07:30:3328.07.2021 07:30:33D00352