Information
Definition
RCD Type B is a residual current device type capable of detecting AC, pulsating DC and smooth DC residual currents. It is normally assessed during product selection, circuit design, installation verification and maintenance of EV charging equipment.
Why it matters
It may be required where DC residual current detection is not otherwise provided or where manufacturer and design requirements call for it. For UK users, it supports safer specification decisions and reduces the risk of misunderstanding how a charger should be protected or installed.
References
Standards and regulations
BS 7671
BS 7671 is the UK national standard for electrical installations, covering the design, erection, inspection, testing and verification of low-voltage electrical systems. Section 722 contains specific requirements for supplies to electric vehicles.
EN 62955
EN 62955 is the UK-relevant BS EN IEC standard for Residual Direct Current Detecting Devices used in Mode 3 EV charging equipment. It is commonly associated with 6 mA DC residual current detection and how EV chargers interact with upstream RCD protection.