Built-in RCD for AC Charging Station

(RDC-DD for Mode-3 EVSE)

IEC standard request for residual current protection
at Mode-3 EV Charging

According to IEC61851-1: 2017 and IEC60364-7-222:2018, the appropriate protective measures against electrical shock at Mode-3 EV chargers shall be
  • Option 1: RCD Type B (IEC 60947-2 type-B mRCD/CBR or IEC 62423 type-B RCCB)
  • Option 2: RCD Type A (IEC 61008-1 type-A RCCB, IEC 61009-1 type-A RCBO or IEC 60947-2 type-A mRCD/CBR ) and RDC-DD (IEC62955 RDC-PD / RDC-MD)
RCDs and RDC-DD shall comply with the standards in the brackets. Also, it is explicitly stated by IEC60364-7-222:2018 that RCD shall disconnect all live conductors. Therefore, it is highly recommended to install a freestanding type-A 30 mA RCD outside the EV chargers, rather than simply relying on the built-in RCD –typically consisting of relays/contactors, an AC/DC residual current sensor and charging controller circuit at an EV charger.

Typical architecture of built-in RCD / RDC-DD
at Mode-3 EV Chargers

· An AC / DC residual current sensor (also called AC / DC leakage current sensor, AC / DC differential current sensor or AC/DC RCM) can be used to configure an RDC-PD (Type A 30 mA complying with IEC 61008-1 / IEC60947-2-Annex M and DC 6 mA complying with IEC 62955) or an RDC-MD (solely DC 6 mA complying with IEC 62955) together with other components and parts in an EV charger, so as to meet the protection request defined in IEC 61851-1 and IEC 60364-7-722.
· Protection against the fatal AC residual current in this configuration – via coordinated activities of the sensor, charging controller, and relays/contactors – is less reliable than the Din-rail RCBOs or RCCBs detecting and trips independently. Therefore, we strongly advocate installing at least a type-A RCD upstream of the EV charger, even if your chargers declare a built-in type-A 30 mA protection.

Our AC/DC residual current sensor family for
AC charging stations

Robust Design

Product with track records in Asia and Europe. High-performance products with high reliability, anti-vibration capability, wide temperature operation etc.

Flexible Installation

Standing-on-PCB, Laying-on-PCB and Hanging-around-main-cable variants are available to meet various kinds of customer request

Fast Detection

Very fast residual current detection- such as a response time of 150 mA AC residual current less than 15 ms – facilitates a broad selection of switching relays and contactors

Trusted Delivery

A dual supply chain with upstream partners from Jiangsu Province(China) and DACH region (Europe) which significantly mitigates delivery risks

BRCS03X AC/DC residual current sensors
– compatible, reliable and affordable

BRCS03X is an AC/DC leakage current sensor product line with robust performance against noise in the system. Its highlights are as follows
  • 5V DC or 12V DC interfaces available for compatible integration
  • Three installation variants facilitating different integration schemes
  • Two fault signal pins for solely DC and AC&DC fault signal output
  • Cost-effective solution of residual current detection for AC EV charger
  • Fast response time facilitating a broad selection of switching devices
  • Compact design with 18mm through-hole for charging cable up to 3P+N 32A