The new version of the CEI EN 61851-1 standard, adopted in Italy in September 2019 by the Italian Electrotechnical Committee (CEI) and in effect since July 5, 2022, mirrors the 2017 international reference standard EN 61851 (also known as IEC 61851), drafted by the International Electrotechnical Commission (IEC). This standard regulates European standards for conductive charging of electric vehicles, with applications on street-side, onboard, and off-board charging infrastructures for alternating current (AC) supply voltages up to 1000V and direct current (DC) up to 1500V.
The document defines the necessary specifications for the charging station to interact with the electric vehicle during the refueling process, covering the characteristics and operating conditions of charging infrastructures, connection components between the power supply equipment and electric vehicles, and general electrical safety requirements. With the growth of the electric market and the parallel spread of new charging infrastructures, nearly 21,000 of which are expected by 2025 in Italy, the CEI EN 61851-1 standard is becoming increasingly relevant and essential for conscious and safe operations. Let’s take a closer look at what it entails.
Objectives of the CEI EN 61851-1 Standard
To ensure the efficiency of charging infrastructures, each system must meet specific safety requirements and comply with the applicable regulations: from design to installation and commissioning, to maintenance. In this sense, the CEI EN 61851-1 standard works to provide a standardized framework for EV charging, promoting interoperability. The electric ecosystem consists of various players, including electric vehicle and charging infrastructure manufacturers, e-mobility service operators and providers, and EV drivers. Each of them must be able to communicate with the others using standardized protocols to create increasingly optimized charging systems.
The CEI EN 61851-1 standard operates in parallel with other standards from the International Electrotechnical Commission to protect EV drivers, service operators, and charging station components. With the installation of electric charging devices in private spaces (such as garages and condominium parking spaces) and public areas (such as parking lots, gas stations, and garages), everyone can access facilities connected to an electrical power supply. However, not everyone is aware of the risks associated with electric power supply, especially in structures exposed to sudden weather conditions. It is therefore essential that charging infrastructures are installed following the highest standards of workmanship.
Safety Requirements
The Fire Department defines “to the highest standards” charging systems for EVs that comply with the CEI 64-8 part 7, section 722 standard and the CEI EN 61851 and CEI EN 62196 series of standards. All components of international charging infrastructures must therefore be designed, installed, and maintained to these high standards. According to research by electrotechnical experts, including the CEI and researchers from ENEA (National Agency for New Technologies, Energy, and Sustainable Economic Development), electric vehicles are no more prone to fires or explosions than traditional vehicles. As with fossil-fuel equivalents, precautionary safety measures should always be in place for EVs.
In this way, the likelihood of ignition and spread of fires and explosions is reduced, providing the users of charging stations and safety operators the opportunity to evacuate the affected area if necessary. To prevent electrical risks, charging infrastructures with public access must undergo regular inspections on a weekly basis by the operator in charge. Additionally, the user of the charging service must have access to portable fire extinguishers that are easily accessible and suitable for use on live electrical systems or equipment. Finally, the EV driver must own a certified vehicle, kept in good working condition, and subject to regular inspections.
Technical Specifications Defined by CEI EN 61851-1
In paragraph 6.2, CEI EN 61851-1 defines four modes of charging an EV from the power supply (Mode 1, 2, 3, 4), which differ in terms of supplied power, charging speed, and type of connection to the charging infrastructure. While the first two types are intended for private, condominium, or corporate contexts, the last two mainly apply to public charging. Mode 3 (standard power charging), in particular, involves the presence of fixed alternating current (AC) charging stations, such as charging pillars or wallboxes, equipped with a Control Pilot and a protection system (PWM). Mode 4 (high power charging), on the other hand, operates on direct current (DC) and therefore requires a converter integrated into the charging station, to which the EV charging cable is connected. These two modes, recommended by the regulation under consideration, include a system to prevent the plugging and unplugging of connectors, to avoid the sudden interruption of current when the EV is charging.
Paragraph 3, on the other hand, defines three types of connection (A, B, C), based on the presence and interaction between the connection cable, mobile connector, and plug. In the case of a type C charging system, where the connection cable and mobile connector are permanently attached to the power supply equipment, a visual inspection of the cable is required to ensure safe charging. Additionally, the insulation of the connection cable must withstand wear, and if fitted with a metal shield, it must be grounded.
The CEI EN 61851-1 standard also outlines the specifications for the safe placement of mobile connectors. These should be located as close as possible to the EV’s parking spot, without using an extension cord, a second power cable, or an adapter. Finally, each fixed socket or mobile connector must supply only one electric vehicle.
Installation and Maintenance Guidelines for Charging Stations
Before using a charging infrastructure, installation must follow precise safety standards. First, potential risks of interference between the charging station and other installations or deposits of potentially flammable materials must be assessed. The charging station should be located, according to Legislative Decree 81/2008, outside classified areas, defined as work areas where the presence of flammable gases, vapors, or dust is likely.
Each charging station must also be equipped with an emergency release coil, positioned in a marked and accessible location for rescue operators, allowing them to “disconnect” the electrical system from the power source in case of an emergency. Also essential are the Control Pilot, which regulates the charging current using PWM (pulse-width modulation) technology, and the Proximity Pilot, which provides the vehicle with information about the charging status with a specific charging current. These controls are part of the mandatory equipment for charging infrastructures as per the CEI EN 61851-1 standard. The document thus provides an overview of the classes to which electric vehicles belong and the charging methods that are internationally compliant. A functional and essential package for a future in green mobility.