Janitza RCM 202-AB Residual Current Monitoring Device


The Janitza RCM 202-AB is employed with current transformers connected for the measurement and monitoring of residual currents of the types A, B and B+ in TN and TT systems (grounded AC systems).

Features include:

  • Residual current measurement using up to two connected current transformers (compatible with all Janitza residual current transformers)
  • Transformer connection monitoring for wire break or short circuits per channel
  • Acquisition, evaluation and monitoring of residual currents of types A, B and B+ to IEC 62020
  • Acquisition of sinusoidal AC fault currents with frequencies of up to 20 kHz (type B+)
  • Acquisition of purely DC currents
  • Measured and extreme values memory with time stamp
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The RCM 202-AB enables continuous monitoring of TN-S systems and complies with DIN EN 62020/VDE 0663/IEC 62020. This refers to residual current monitoring devices which check circuits for the occurrence of a residual current and trigger an alarm if a set alarm value is exceeded. The two-channel residual current monitoring device is suitable for the monitoring of residual currents type A to Type B+.

For standard compliant type A measurement on DIN rails the Janitza RCM 201-ROGO can be used.


Measuring channels

  • Two current transformer connections (compatible with all Janitza residual current transformers)
  • AC/DC measurement range: 10 mA … 20 A


Measuring display and operation

  • Two-colour LED display (128 x 64 pixels)
  • 3-button control
  • Self test and check indicator
  • German, English and Spanish user guidance can be selected


RCM analysis variables

  • Individual limit values can be set for type A, type B, and type B+
  • Individual frequencies for 1-2000 Hz
  • Spectrum display for 2-20 kHz



  • 2 digital alarm outputs, 2 freely scalable analogue outputs



  • RS485 interface (protocol: Modbus RTU)
  • Compatible with all communications-capable Janitza Modbus master devices


High measurement accuracy

  • From 2% to final value
  • Measurement of residual currents in the measurement ranges 5 / 10 / 25 / 125 A


Standards – compliant to IEC 62020

  • Recording, evaluation and monitoring of type A residual currents



  • Rogowski RCM current transformers for large cable cross sections and busbars up to 4000 A


Alarm function

  • Configurable limit values and alarm output via digital output and Modbus

Download the Janitza RCM 202-AB and 201 ROGO brochure here:

Download the 2021 Janitza Product Catalogue here:

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