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.


  • 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 switch-mode power supplies

Product Features

  • Monitoring for unearthed AC and DC systems with galvanically connected rectifiers or inverters
  • Measurement of the nominal system 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 500 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 1…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 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

Gain access to our downloadable files by simply providing your email address below.