With major vehicle manufacturers adopting the North America Charging System (NACS) for their future electric vehicles, the use of EV charging adapters has become increasingly common in the marketplace. This shift towards NACS began in May 2023 and has led CharIN to focus on developing best practices and recommendations for adapter specifications and safe use. These efforts aim to assist industry standard development organizations such as SAE International (SAE), Underwriters Laboratories (UL) and International Organization for Standardization (ISO) in creating standards to ensure compatibility and safety.
Both CCS and NACS have similar underlying technology. However, their charging couplers differ necessitating the use of adapters for compatibility. As more EVs with NACS charging ports enter the market utilizing existing CCS infrastructure and coincidentally legacy EVs with CCS charging ports utilizing NACS infrastructure, adapters are expected to play a crucial role in ensuring a smooth transition and providing charging accessibility for all EV drivers.
While CharIN has advocated for using a native charging connector to avoid adapters, the widespread adoption of both NACS and CCS necessitates their continued use to ensure charging accessibility. This reliance on adapters is likely to persist until a dominant standard emerges and SDO certified SAE J3400 compliant connectors are widely deployed.
Many currently available adapters lack proper safety features and pose considerable public safety risks, including potential electrical shock and fire hazards. However, efforts are underway to improve safety and standardization:
- SAE International (SAE) J3400/1 Technical Information Report (TIR) for EV charging adapters, expected to be available within Q2 2025. This document provides guidelines for adapter design and performance to ensure safety, interoperability, and use compatibility.
- Underwriters Laboratories (UL) has published UL 2252, a safety standard specifically for EV charging adapters. Manufacturers can already certify their adapters to the standard. This certification provides standard industry testing specifications.
- International Organization for Standardization (ISO) has recently included within ISO15118-202 Publicly Available Specification (PAS) for communication between electric vehicles (EVs) and charging stations (EVSEs) a new feature, ESDP or Extensible Service Discovery Protocol. ESDP enables early communication, enhanced monitoring capabilities and optimized charging parameters. ESDP contributes significantly to the safety, reliability, and durability of adapter use in EV charging, regardless of a NACS to CCS or CSS to NACS use scenario.
By adhering to these standards and seeking proper certifications, manufacturers can help mitigate the risks associated with EV charging adapters and ensure consumer safety.
Due to documented evidence from multiple catastrophic charging event failures involving charge coupler adapters, and with the recent recalls of adapters by the U.S. National Highway Traffic Safety Administration (NHTSA) (as listed on the NHTSA website), CharIN is strengthening its initial recommendations to OEM EV & EV charging adapter manufacturers, industry NHTSA reporting protocol, and charge point operators (CPO) regarding these adapters.
1. To ensure the safety and reliability of EV charging adapters, CharIN strongly urges OEMs and EV charging adapter manufacturers, distributors, and retailers to take the following actions:
- Use only UL 2252 certified and/or Original Equipment Manufacturer (OEM) approved adapters.
- Mandate Adapter Certification: Given risks associated with the use of unauthorized adapters, require that all adapters be certified, approved, engineered, or provided by the OEM manufacturer of a specific customer’s vehicle and/or require that all adapters undergo rigorous testing and certification by 3rd party nationally recognized testing laboratory (NRTL) to meet the UL 2252 standard, adhere to SAE J3400/1 recommended practices and comply with ISO 15118-202 ESDP EV / EVSE communication protocols. This will help ensure that adapters are safe, reliable, and compatible with various charging systems.
- Communicate Safety Guidelines: EV OEMs must proactively inform their dealers and vehicle owners about the potential risks associated with using adapters not provided by the customer’s OEM and/or non-certified adapters. Clearly communicate that using adapters other than those provided with the customer’s vehicle and/or UL 2252 certified ones may result in:
- Severe damage to the vehicle
- Damage to the EV charging infrastructure
- Damage to surrounding facilities
- Risk to consumer safety
2. To further enhance safety and accountability within the EV charging adapter landscape, CharIN recommends that the industry incorporate mandatory reporting to NHTSA as part of their adapter field incident response protocol.
- Mandatory Reporting Response Protocol: This recommendation aligns with NHTSA's specific request to CharIN on September 18, 2024, emphasizing the importance of data collection and analysis in identifying potential safety trends and addressing emerging risks associated with adapter use. By promptly reporting incidents to NHTSA’s Ashley Simpson (ashley.simpson@dot.gov) or Transport Canada by calling 1-800-333-0510 or website, manufacturers and stakeholders can contribute to a more comprehensive understanding of adapter performance and facilitate proactive measures to improve safety, reliability and Federal Motor Vehicle Safety Standards (FMVSS). By taking these steps, the industry can collectively work towards minimizing the risks associated with EV charging adapters and ensure a safe and reliable charging experience for all EV drivers.
3. Charge Point Operators (CPOs) should take proactive steps to ensure the safety and compatibility of these devices on their networks. CharIN recommends the following actions for CPOs:
- Communicate Adapter Usage Guidelines: Clearly communicate to EV drivers the importance of using only adapters provided by the manufacturer of the customer’s vehicle and/or certified adapters. Utilize multiple channels to disseminate this information, including:
- Update Terms of Use: Incorporate a requirement for UL 2252 certification within their Terms of Use or other customer-facing agreements to clearly establish the expectation for adapter safety and compliance.
- On-site Signage: Prominently display signage on EVSE dispensers that clearly indicates the requirement for UL 2252 and SAE J3400/1 compliant adapters and warns against the use of uncertified adapters.
- Public Communication Channels: Utilize websites, mobile apps, and social media platforms to inform EV drivers about adapter safety, compatibility requirements, and the potential risks associated with using uncertified adapters.
- Collaboration with OEMs: Work closely with EV OEMs to align messaging and ensure consistent communication regarding adapter usage guidelines.
- Implement ISO 15118-202 ESDP and UL2252 Over Temperature Protection Test: Incorporate a requirement and collaboration with EV OEMs to develop seamless ESDP functionality, UL2252 Certification Compliance to improve safety when using adapters by enabling the following:
- Early Adapter Verification: ESDP allows the EVSE to immediately identify the presence and type of adapter. This ensures the charging station can verify compatibility and configure itself correctly before any power transfer occurs, reducing the risk of electrical faults or damage.
- Temperature Monitoring: ESDP implementation enables charging interface maximum temperature detection. UL2252 full compliance requires an Over Temperature Protection Test.
CharIN remains committed to expediting the development of robust standards for EV charging couplers and systems. We are actively collaborating with key stakeholders, including NHTSA and the Joint Office of Energy and Transportation (JOET), to ensure these standards are comprehensive, safe, and support the widespread adoption of EVs. Our ultimate goal is to facilitate an EV infrastructure build-out that eliminates the need for adapters altogether, thereby mitigating the inherent risks associated with their use.
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