SAE J3400 Charging Connector
In December 2023, SAE International published the Technical Information Report (TIR) for J3400, which is an EV charging connector standard based on the North American Charging Standard (NACS) connector. The standardization of NACS as J3400 ensures that any supplier or manufacturer will be able to use, manufacture, or deploy the J3400 connector on electric vehicles (EVs) and at charging stations across North America.
The NACS connector is one of several connector types that enable fast charging of electric vehicles (EVs), in addition to the Combined Charging System (CCS1) and CHAdeMO. NACS can also be used for AC Level 1 and Level 2 charging and is compatible with the J1772 connector for these charging speeds through an adapter.
In May 2023, the Federal Highway Administration (FHWA) published requirements that allow for J3400/NACS adapters to be installed on all federally funded direct-current fast charging (DCFC) chargers as long as there is also a CCS1 connector.
In August 2024, the SAE EV Coupler Task Force voted to establish the J3400 standard as a Recommended Practice, marking a significant step forward in the standardization process. This milestone brings the J3400 standard closer to official publication in a format that can be cited in regulations and used by manufacturers with confidence.
Background
DCFC enables rapid charging of EVs. There are three types of DCFC connectors in the United States:
CCS1
SAE CCS1
CHAdeMO
J3400
in development from NACS
Most EV models on the market today charge using the CCS1 connector, but most vehicle manufacturers have made commitments to incorporate the J3400 connector beginning in 2025. These companies have also indicated that they will provide J3400 adapters to owners of CCS vehicles beginning in 2024.
Terminology
When building out EV charging infrastructure, it is helpful to become familiar with industry terminology. The following terms are commonly used:
- Adapter: Hardware that allows an EV to connect to a charger/station that it otherwise could not connect to directly. There are a variety of adapters for different connector types.
- Charger cable: Delivers power from the power source/ charger to the EV.
- Connector: Plugs into a corresponding vehicle charging inlet and makes an electrical connection to charge the EV. Connectors are sometimes also called plugs.
- Charger port or electric vehicle supply equipment (EVSE) port: Each port on a charger can charge a single EV. A port may be able to use multiple connector types (e.g., CHAdeMO, CCS1, NACS). In some cases, multiple connector options may be provided for each port, allowing EVs to use the connector they need, but only one vehicle will charge at a port at a time. The unit that houses ports is sometimes called a charging post, which can have one or more EVSE ports.
- CCS1 connector: Also known as SAE J1772 combo, the Combined Charging System 1 (CCS1) connector uses the same five pin layout for the SAE J1772 connector used for AC Level 1 and Level 2 charging with two additional bottom “DC” pins for use with a DCFC.
- EV charging station location: A site with one or more charging ports at the same address.
- NACS connector: Originally developed by Tesla, this connector works for AC (L1, L2) and DC charging utilizing the same pins for AC and DC power transfer.
- SAE J3400: The SAE standard currently in development for the NACS connector to enable its use across the EV industry.
- Electric Vehicle Charge Controller (EVCC): An embedded controller in the EV responsible for handling communication between an EV and charging station. Standardized communication protocols are key to ensuring compatibility and interoperability between different charging stations and EVs.
- CCS1
- Standardized through SAE J1772
- Developed by industry over a decade of deliberation and field testing.
- J3400
- SAE TIR published in December 2023, Recommended Practice (RP) document expected by September 2024.
- Certification via UL-2251 needs update to both NACS and J3400
- UL Adapter Certification by Q3 2024.