Innovative technologies for safe handling of electrical power to achieve high availability

We offer you first-class quality and safety combined with global service and every support in resolving your monitoring problems.

  • Electrical safety for unearthed power supplies (IT systems)
  • Insulation monitoring equipment, insulation fault location systems
  • Power supplies for medical applications
  • Measuring and monitoring relays
  • Electrical safety for earthed power supplies (TN systems)
  • Using renewable energies efficiently: wind power, photovoltaics
  • Test systems for electrical equipment and medical technology


The AC/DC sensitive residual currentmonitoring module RCMB104, with patented measurement method, is used incombination with a measuring current transformer CTBC17 or W15BS and a type A RCD which has to be provided in the installation forfault current monitoring of AC charging systems for electric vehiclesin which AC or DC fault currents can occur.The rated voltage Un is 250 V and the rated current (charging current) In = 1x48 A / 3x32 A. The RCMB104 is suitable for integrationinto a charging unit (IC-CPD, wall box) according toIEC 61851-22, IEC 62752 and UL 2231-2.

The RCMB104 is only intended for purchase by the manufacturerof the charging system and not for end users!

More information:


  • Three outputs (DC, RMS, Error)
  • Measuring range ±300 mA
  • Residual current resolution 0.2 mA
  • Patented measurement technology (Patents: EP 2 571 128 / US 9,397,494 / ZL 201210157968.6 / CN 103001175, EP 2 813 856)
  • Load current up to 48 A r.m.s. (single-phase) or 3 x 32 A r.m.s. (three-phase)
  • Fault output (integrated self monitoring and test functions)
  • High insensitivity to external interferences
  • Available variants for application according to DIN EN 61851-22/IEC 62752 and UL 2231-2
  • Wide range of use even in severe environments (e.g. in the event of external interference fields)
  • In applications according to DIN EN 61851-22 or IEC 62752, the RCMB104 can replace a type B RCD when combined with a type A RCD and a suitable switching device (e.g. a power relay).


  • AC charging systems for electric vehicles

Downloads for RCMB104

Handbücher RCMB104 2.2 MB DE17.11.2021 06:42:01D00294
Handbücher RCMB104 2.2 MB EN17.11.2021 06:42:01D00294
Datenblätter RCMB104 675.1 KB DE24.11.2021 10:21:46D00294
Datenblätter RCMB104 627.0 KB EN24.11.2021 10:21:56D00294
Datenblätter W15BS 404.8 KB DE26.02.2020 14:39:39D00371
Datenblätter W15BS 401.9 KB EN25.02.2020 11:19:47D00371
Technische Informationen Stellungnahme Prüfung 6mA DC Fehlerstrom 450.2 KB DE07.06.2022 12:37:32

Optional accessories for RCMB104

RCMB104 Variants

TypeDescriptionArt. No.
RCMB104-10…2 kHz IEC 6/30 mAB94042480
RCMB104-20…2 kHz UL 2231 5/20 mAB94042481
W15BSMeasuring current transformer Ø = 15 mm,
Connection cable 1470 ±30 mm
W15BS-02Measuring current transformer Ø = 15 mm
Connection cable 180 ±30 mm
W15BS-03Measuring current transformer Ø = 15 mm
Connection cable 325 ±25 mm
CTBC17Measuring current transformer Ø = 17 mmB98080070
CTBC17-Cable180MMConnection cable 180 ± 30 mmB98080540
CTBC17-Cable325MMConnection cable 325 ± 25 mmB98080541
CTBC17-Cable1470MMConnection cable 1470 ± 30 mmB98080542