•  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.