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What Type Of RCD Do I Need For My EV Charger?

What Type Of RCD Do I Need For My EV Charger?

Liu Hualei | Bituo Technik

Ensuring electrical safety during Electric Vehicle (EV) charging is paramount. Residual Current Devices (RCDs) serve as the critical line of defense against electric shock. However, determining whether the RCD installed upstream of an EV charger provides adequate protection can be challenging. This guide explains how to select the correct type of RCD for home EV charger installations, ensuring compliance and safety.

Step 1: Understand IEC/EN Standards for Residual Current Protection

The IEC/EN 61851-1:2017 and IEC 60364-7-722:2018 standards specify the protective measures required for Mode-3 EV charging systems (typically wall-mounted AC chargers) as follows:

  • 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) combined with an RDC-DD (IEC 62955 RDC-PD or RDC-MD)

Step 2: Verify the EV Charger's Built-in Protection

Review the datasheet of your EV charger. Manufacturers typically declare one of the following types of integrated residual current protection:

  • Type-A 30mA RCD (IEC 61008-1 / IEC 61009-1 / IEC 60947-2)

  • Type-A 30mA RCD (IEC 61008-1 / IEC 61009-1 / IEC 60947-2) + RDC-MD (IEC 62955)

  • RDC-MD (IEC 62955)

  • Type-B RCD (IEC 62423 / IEC 60947-2)

If a manufacturer only claims "AC 30mA & DC 6mA compliance" without referencing specific RCD or RDC-DD standards, contact them for clarification. If clarification is unavailable, the safest approach is to install a Type-EV RCD (an integrated Type-A RCD and RDC-DD) or a Type-B RCD upstream of the charger.

Picture showing External RCD installed

Step 3: Select the Appropriate External RCD

Based on the EV charger's built-in protection, use the following matrix to select the correct external RCD:

Manufacturer Declaration of integrated RCD type at EV charger

External RCD installation meeting standard request

External RCD installation recommended by our experts

Type-A 30mA RCD (IEC 61008-1 / IEC 61009-1 / IEC 60947-2)

Type-B RCD (IEC 62423 / IEC 60947-2) or RDC-DD (IEC 62955)

Type-B RCD (IEC 62423 / IEC 60947-2) or Type-EV RCD  (IEC 61008-1 / IEC 61009-1 + IEC 62955)

Type-A 30mA RCD(IEC 61008-1 / IEC 61009-1 / IEC 60947-2) + RDC-MD (IEC 62955)

Not needed in theory

Type-A 30mA RCD (IEC 61008-1 / IEC 61009-1 )

RDC-DD (IEC 62955)

Type-A 30mA RCD (IEC 61008-1 / IEC 61009-1 )

Type-A 30mA RCD (IEC 61008-1 / IEC 61009-1 )

Type-B RCD (IEC 62423 / IEC 60947-2)

Not needed in theory

Type-A 30mA RCD (IEC 61008-1 / IEC 61009-1 )

Expert Recommendation: We strongly advise installing an external Type-A 30mA RCD, even if the EV charger claims full integrated compliance with IEC 61851-1 and IEC 60364-7-722. Ensuring that built-in components fully meet the rigorous testing requirements of dedicated Type-A RCD standards (IEC 61008-1/61009-1) is challenging. A dedicated DIN-rail Type-A 30mA RCD is a cost-effective (typically 20-30 EUR) and highly reliable investment, effectively turning the charger's built-in protection into a secondary backup.

Step 4: Installation Guidelines

Once the correct RCD is selected, it must be installed by a qualified professional. Always consult local regulations, as many jurisdictions legally require a certified electrician to perform RCD installations.

Special Notes: The IEC standards referenced in this guide are widely adopted across Europe, Asia, and Africa.

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