E. Dold & Söhne GmbH & Co. KG

Tel.: +49 7723 654-0
E-Mail: dold-relays@dold.com

• Representatives
• Contact form

Direct contact for orders

Tel.: +49 7723 654-454
E-Mail: ab@dold.com

Direct contact for technical questions

Tel.: +49 7723 654-459
E-Mail: rv@dold.com

Direct contact for shipping inquiries

Tel.: +49 7723 654-455
AN 5873

Insulation monitor

AN 5873


Auxiliary voltage

Alarm value


  • 0031599
  • AN5873.11/101 UH AC230V 50K-OHM
The insulation monitor AN 5873 of the series VARIMETER IMD monitors the ground resistance of... more

Product description

The insulation monitor AN 5873 of the series VARIMETER IMD monitors the ground resistance of ungrounded DC and 3-phase AC voltage systems (IT-systems) with nominal voltage up to DC 0 ... 1000 V and 3 AC 24 ... 690 V. The unit detects symmetrical as well as unsymmetrical faults. The separate auxiliary supply allows also monitoring when the system is without voltage. To indicate the actual ground resistance value the unit has an LED chain and an analogue output. When a fault is detected the relay switches and the red LED lights up.

Technical specifications

Width: 100 mm
Response value: 50 kΩ
IMD type: AC, DC, AC/DC
Nominal voltage IT system: 3AC 24 - 690, DC 0 - 1000 V
Auxiliary voltage: AC
Enclosure design: Switch cabinet
Earth fault indicator: Yes
Connection for indicator: Yes
Response value type: Fixed
Type: AN 5873


  • Preventive fire and system protection
  • Insulation monitoring of DC- and 3 AC-systems up to 1000 V and 3 AC 690 V nominal voltage
  • No additional coupling device required
  • Monitoring also with voltage-free mains


  • Insulation monitoring according to IEC/EN 61 557-8
  • Fixed response value RAN
  • Internal reset button
  • External reset and test button can be connected
  • LED indicator
  • 1 changeover contact
  • Programmable for manual reset or hysteresis function
  • Analogue output for insulating value
  • External connection of indicating instrument possible
  • As option de-energized on trip or energized on trip
  • Width 100 mm