IEC 61851-25:2020

Overview

IEC 61851-25:2020 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies the requirements for direct current (DC) electric vehicle supply equipment (EVSE) where protection relies on electrical separation. This standard applies specifically to DC charging systems designed to charge electric road vehicles with rated supply voltages up to 480 V AC or 600 V DC and rated output voltages not exceeding 120 V DC, with maximum output currents up to 100 A DC.

This document provides essential guidelines for the design, operation, and safety of DC EV supply equipment that utilizes electrical separation to protect the secondary circuit from the primary power source. It also covers the control and communication protocols between the DC EVSE and the electric vehicle (EV). Notably, requirements for bi-directional power flow and charging of specialized vehicles like trolley buses or off-road vehicles are excluded from this standard.

Key Topics

• Electrical Separation for Safety: The core aspect of IEC 61851-25 is ensuring that the secondary circuit (connected to the EV) is electrically isolated from the primary supply circuit. This separation enhances user and equipment safety by minimizing risk of electric shock.

• Operating Conditions & Characteristics: Specifies the rated supply voltages, output current limits, and electrical characteristics necessary for the reliable and safe functioning of DC EVSE under different operational environments.

• Control and Communication Requirements: Defines the communication interface and protocols required between the EV supply equipment and the electric vehicle to manage charging operations safely and effectively.

• Protection Against Electric Shock: Outlines measures for preventing electric shock incidents, including design, construction, and testing of the supply equipment, in compliance with IEC 61140.

• Environmental Considerations: Includes additional requirements for DC EVSE operating in special conditions such as hazardous areas with combustible gases, high-altitude locations above 2000 meters, and onboard ships, ensuring versatility and safety in diverse settings.

• Construction and Testing: Establishes structural design requirements and verification tests for overload, short-circuit protection, automatic reclosing, marking, instructions, and emergency disconnection features.

• Exclusions and Limitations: Clarifies that the standard does not cover electrical devices and components within the EVSE (subject to their own product standards), safety aspects related to maintenance, electromagnetic compatibility (EMC) for equipment on the EV, or off-board energy storage systems.

Applications

IEC 61851-25:2020 is crucial for manufacturers, engineers, and operators involved in:

• Designing DC charging stations for electric road vehicles where electrical separation provides protection.
• Ensuring compliance with international safety and interoperability standards for DC EV supply equipment up to specified voltage and current ratings.
• Deploying DC EVSE in various challenging environments such as industrial sites with hazardous materials, high-altitude areas, and maritime vessels.
• Developing control and communication systems that interface securely and reliably between charging equipment and electric vehicles.
• Implementing safety measures that prevent electric shock and other electrical hazards during EV charging operations.

This standard supports the global growth of electric vehicle infrastructure by promoting safe, reliable, and standardized DC conductive charging solutions.

Related Standards

• IEC 61851-1:2017: General requirements for electric vehicle conductive charging systems, which IEC 61851-25 supplements by focusing on electrical separation for DC supply equipment.
• IEC 61140: Protection against electric shock – Common aspects for installation and equipment, providing foundational principles for electrical separation used in this part.
• IEC 61851-21-1: Electromagnetic compatibility (EMC) requirements for equipment on the EV while connected, referenced as complementary but excluded from this document.
• Other parts of IEC 61851 series addressing AC charging modes, communication protocols, and safety requirements for a comprehensive framework of EV conductive charging.

Keywords: IEC 61851-25, DC EV supply equipment, electric vehicle charging standard, electrical separation, electric vehicle conductive charging, DC charging safety, electric vehicle supply equipment, EVSE standards, electric shock protection, DC charging communication, hazardous environment charging.