Information
Definition
An Open combined Protective and Neutral conductor Detection Device (OPDD) is a device or integrated EV charging function designed to detect conditions associated with an open PEN conductor fault and disconnect, or initiate disconnection of, the affected circuit or equipment. IET 01:2024 sets definitions, requirements and tests for OPDD behaviour.
Why it matters
It matters because an open PEN fault can create hazardous touch voltages on connected exposed-conductive-parts, including an electric vehicle. UK specifiers and installers need to understand OPDD claims, PME protection wording and how the product’s behaviour relates to BS 7671 and IET 01.
References
Standards and regulations
IET 01
IET 01:2024 is a non-statutory IET standard and technical specification for Open combined Protective and Neutral conductor Detection Devices used with EV charging equipment. It sets out definitions, requirements and tests for how discrete or integrated OPDD functions should respond to open PEN conductor faults.
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.