Information
Definition
A Residual Direct Current Detecting Device detects residual DC current in Mode 3 EV charging equipment. It is normally assessed during product selection, circuit design, installation verification and maintenance of EV charging equipment.
Why it matters
It helps prevent DC residual current from blinding or impairing upstream residual current protection. 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
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.
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.