BEAMA Guide to RCD Protection of EV Charging Installations

About this manual

This guide provides information on the selection and application of Residual Current Devices (RCDs) for the protection of electric vehicle (EV) charging installations. It covers the requirements for RCDs, the effects of DC fault currents on RCDs, and the use of RDC-DDs, RDC-MDs, and RDC-PDs in EV charging systems.

The document details specific regulations from BS 7671, including the need for Type A, Type B, or Type F RCDs, and explains how to handle DC fault currents exceeding 6 mA. It further classifies Residual Direct Current Detecting Devices (RDC-DDs) into RDC-MDs and RDC-PDs, describing their construction and application in Mode 3 charging scenarios.

What's inside

• Introduction
• Abbreviations and Definitions
• RCD selection
• Effects of DC fault currents on RCDs
• RDC-DDs
• RDC-MDs
• RDC-PDs
• RDC-DD testing
• RCD protection for Electric Vehicle wireless power transfer

Frequently asked questions

What type of RCD is required for EV charging installations unless supplied by a circuit using electrical separation?

An RCD of at least Type A shall be provided.

What is the minimum DC fault current level that RCDs must protect against in EV charging installations?

Protection shall be provided against DC fault currents exceeding 6 mA.

What are the two types of RDC-DDs classified under BS IEC 62955?

RDC-MDs and RDC-PDs.