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Residual Current Protection

Summary

Our charging units are designed to offer superior safety through built-in residual current protection, according to IEC 60947-2 annex M and IEC 62955 standards. This ensures the effective detection and disconnection of fault currents, providing robust protection for both users and vehicles.

Key Safety Features:

  • DC Fault Protection with RDC-DD: Integrated with a Residual Direct Current Detection Device (RDC-DD) complying with IEC 62955, offering disconnection when direct current (DC) fault levels exceed 6 mA.
  • 30 mA AC Protection: Detects and mitigates alternating current (AC) residual faults of 30 mA or higher to prevent electric shock according to IEC 60947-2 annex M.
  • Fast Disconnection: In case of a fault, the system responds faster than traditional solutions.
  • Automatic Testing: Before each charge or at least 24 hours, the built-in residual current device will automatically perform a selfcheck. The button at the right bottom of the charger is available for manual selfcheck.

Whether an external RCD is required depends on the actual installation conditions on site and the approval of the authorized installer during the installation process. Please note that regulations may be different depending on the region or country of residence.

The following is an extract from IET Wiring Matters: Issue 100 - May 2024, and concerns the requirement of a dedicated RCD per EVSE for the UK market:

Can I use an EVSE with an integrated RCD?

Some manufacturers state that EVSE contains integrated RCDs.

A question often asked is “if additional protection by an RCD is integrated within the EVSE could RCD protection be omitted in the dedicated/final circuit?”

After all, the requirement for RCD protection is to be provided for the socket-outlet and not the final circuit.  

BS 7671:2018+A2:2022 does not dictate the location for the RCD. Regulation 722.531.3.101 of BS 7671:2018+A2:2022 states that “except where provided by the EV charging equipment”, protection against DC fault current shall be provided by a Type B RCD or a Type A or Type F in conjunction with an RDC-DD. This is further clarified in Note 3 to Regulation 722.531.3.101. So, it is clear that it is acceptable to locate an RCD within the EVSE.

The type of RCD, however, is specified in Regulation 722.531.3.101 of BS 7671:2018+A2:2022. RCDs are required to comply with one of the following standards, BS EN 61008-1, BS EN 61009-1, BS EN 60947-2 or BS EN 62423. If the RCD included in the EVSE complies with one of these standards, then it could be used for additional protection for the electric vehicle charging point without the need for additional RCD protection upstream.

Often RCDs built in to EVSE, i.e. integrated into the printed circuit board (PCB), do not fully conform to any of the standards required by Regulation 722.531.3.101 of BS 7671:2018+A2:2022 or Clause 8.5 of BS EN IEC 61851-1:2019.

Updated on 10 Mar 2025