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  • Insulation monitoring device for AC IT systems
  • Application control circuits
  • According to IEC 61557-8
  • Two separately configurable response values
  • Multi-functional LC display

The ISOMETER® IR420-D4 monitors the insulation resistance of unearthed AC control circuits (IT systems) 0…300 V. If the systems to be monitored include DC components, such as switched-mode power supplies or solenoid valves, the display and operating characteristics may be affected.
The display and response values apply to pure AC systems. An external supply voltage allows de-energised systems to be monitored too.

  • Features
  • Applications
  • Accessories
  • Ordering information
  • Downloads
  • Insulation monitoring for IT control circuits AC 0…300 V
  • Two separately adjustable response values
  • Preset function (automatic assignment of basic parameters)
  • Connection monitoring system/earth
  • LEDs: Power On, Alarm 1, Alarm 2
  • Internal/external test/reset button
  • Two separate alarm relays (one changeover contact each)
  • N/O or N/C operation, selectable
  • Fault memory behaviour, selectable
  • Self monitoring with automatic alarm message
  • Multi-functional LC display
  • Adjustable response delay
  • Two-module enclosure (36 mm)
  • RoHS-compliant
  • Push-wire terminal (two terminals per connection)
  • AC control circuits in the industrial sector, mechanical engineering, power plants, elevators, automation systems etc.
  • AC control and auxiliary circuits in accordance with IEC 60204-1 / DIN EN 60204-1 Electrical equipment of machines
  • AC auxiliary circuits in accordance with DIN VDE 0100-725 (VDE 0100-725)
  • Smaller AC IT systems such as lighting systems, mobile generators


Optional accessories for ISOMETER® IR420-D4

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

Variants of ISOMETER® IR420-D4

TypeNominal system voltage* UnSupply voltage* USResponse value RanSystem leakage capacitance CeArt. No.**
IR420-D4-1AC 0…300 V, 42…460 HzDC 9,6…94 V /
AC 16…72 V, 42…460 Hz
1…200 kΩ< 20 µFB71016409
IR420-D4-2AC 0…300 V, 42…460 HzDC 70…300 V /
AC 70…300 V, 42…46 Hz
1…200 kΩ< 20 µFB71016405
* absolute values
**(B7… = push-wire terminal / B9… = screw-type terminal)

Downloads for ISOMETER® IR420-D4



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