Bender ISOMETER isoPV425 with AGH420


The ISOMETER® of the isoPV425 series monitors the insulation resistance of unearthed AC/DC
main circuits (IT systems) with nominal voltages of 3(N)AC, AC, AC/DC 0…690 V or DC 0…1000
V. DC components existing in AC/DC systems do not influence the operating characteristics. A
separate supply voltage allows deenergised systems to be monitored as well. The maximum
permissible system leakage capacitance is 500 μF.

Product Details


  • Insulation monitoring for unearthed systems AC, AC/DC 0…690 V, DC 0…1000 V
  • Nominal system voltage measurement with undervoltage/overvoltage detection
  • Measurement of the voltages system to earth (L+/PE and L-/PE)
  • Measurement of the system leakage capacitance
  • BMS interface
  • Information about the point of fault L+/L- via display and relay contacts
  • Automatic adaptation to the system leakage capacitance up to 500 μF
  • Supply voltage range DC 24…240 V/AC 100…240 V
  • Self monitoring and connection monitoring system/earth with automatic notification
  • LEDs: Power On, Alarm 1, Alarm 2
  • Internal/external test/reset button
  • Two alarm relays with single pole (one N/O contact each)
  • N/O or N/C operation, selectable
  • Fault memory behaviour, selectable
  • Multi-functional LC display
  • Adjustable response delay
  • Compact two-module enclosure (36 mm) plus coupling in a two-module enclosure
  • Quick wiring by push-wire terminals


  • AC, DC or AC/DC main circuits
  • Solar systems with directly connected inverters
  • Solar systems with high system leakage capacitances
  • Solar systems with high but slow voltage fluctuations
  • Systems including switched-mode power supplies