What is the difference between CCS, NACS, and CHAdeMO?

CCS uses Type 1/2 AC pins plus two DC pins and dominates Europe and North America. NACS (now SAE J3400) uses the same compact pin set for both AC and DC up to 1000V. CHAdeMO originated in Japan and supports bidirectional V2X power flow up to 400 kW.

Why do high-power DC chargers need liquid cooling?

Continuous current above 350 A would push copper contact temperature rise past the IEC 62893 50 K limit. Liquid-cooled cable assemblies circulate coolant through the connector body to keep contact temperatures within safe limits at 500 A and beyond.

What is the maximum power for CCS2 fast charging?

CCS2 supports up to 350 kW at 800 V with liquid-cooled cables, and newer 800 V architectures push peak rates toward 500 kW in pilot deployments.

Is NACS the same as Tesla's old connector?

Yes — Tesla opened its connector design in 2022. SAE standardized it as J3400 in 2023, and it is now the North American charging standard adopted by most automakers.

GB/T 27930 is the Chinese DC fast-charging communication protocol, paired with the GB/T 20234.3 connector. It defines handshake, parameter negotiation, and charging control over CAN between the vehicle BMS and off-board charger.

Connector Basics

High-Power EV Charging Connector Guide: Standards, Thermal Design, and Safety

September 3, 2026 4 min read

Tags:

#CCS connector #EV charging connector #liquid cooled charging cable #NACS #SAE J3400

High-power EV charging connectors combine regional interoperability, touch-safe high voltage, continuous-current thermal performance, locking, communication, and repeated outdoor use. Start with the target market and charging architecture, then validate the complete inlet–plug–cable–cooling system under worst-case operating conditions.

Quick Reference

Charging Standard	Power	Voltage	Current	Connector Type
Mode 2 (portable)	Up to 3.7kW	230V AC	16A	Standard IEC 62196 Type 2
Mode 3 (AC charging)	3.7–43kW	230–400V AC	16–63A	IEC 62196 Type 1/2
Mode 4 (DC fast)	50–350kW+	200–1000V DC	125–600A	CCS1, CCS2, CHAdeMO
CHAdeMO	50–400kW	up to 1000V DC	up to 400A	CHAdeMO (Japan)
NACS (North America)	Up to 250kW+	1000V DC	up to 500A	NACS (Tesla standard)
GB/T (China)	50–500kW	up to 1000V DC	up to 600A	GB/T 20234

1. The EV Charging Connector Landscape

EV charging connectors are safety-critical, high-current, high-voltage components. Unlike most connector categories, they are standardized per region:

Region	AC Connector	DC Fast Connector
Europe	Type 2 (Mennekes)	CCS2, CHAdeMO
North America	J1772 (Type 1)	CCS1, CHAdeMO, NACS
China	GB/T AC	GB/T DC
Japan	Type 1 (J1772)	CHAdeMO

2. CCS vs CHAdeMO vs NACS

CCS (Combined Charging System)

The global leader for DC fast charging. Combines AC pins with two large DC pins in one connector.

Parameter	CCS1 (NA)	CCS2 (EU)
Max power	350kW+	350kW+
Voltage	up to 1000V	up to 1000V
Current	500A+	500A+
AC compatible	J1772	Type 2

CHAdeMO

Japanese standard, common in Asia and with older EVs (Nissan Leaf):

Parameter	Specification
Max power	400kW (latest)
Voltage	up to 1000V
Current	up to 400A
Communication	CAN bus

NACS (North American Charging Standard)

Tesla’s connector, now adopted as SAE J3400. Rapidly becoming the NA standard for DC fast:

Parameter	Specification
Max power	250kW+ (up to 350kW planned)
Voltage	up to 1000V
Current	up to 500A
AC + DC	Single connector does both
Compact	Smaller than CCS1

3. High-Current Contact Design

At 500A, the connector contacts face extreme thermal stress:

Current	Contact Resistance (0.5mΩ)	Heat at Contact
125A	0.5mΩ	7.8W
250A	0.5mΩ	31W
500A	0.5mΩ	125W

Contact resistance is everything. At 500A, a 1mΩ contact generates 250W of heat — enough to melt the housing. High-power EV connectors use:
– Large contact surface area (multiple parallel contacts)
– Silver-plated contacts (lowest resistance)
– Liquid cooling (for >350kW stations)
– Temperature sensors integrated into the connector

4. Safety and Certification

EV charging connectors must meet rigorous safety standards:

Standard	Scope
IEC 62196-1/2/3	Plugs, sockets, connectors for EV charging
IEC 61851	Conductive charging system
SAE J1772	NA AC charging
SAE J3400	NACS standard
UL 2251	NA EV charging equipment
GB/T 20234	China EV connectors
ISO 15118	Vehicle-to-grid communication

5. Design and Sourcing Checklist

Define the regional interface, maximum voltage, continuous and peak current, conductor size, cooling method, cable length, bend radius, locking strategy, temperature-sensor locations, environmental rating, and required certifications. Do not size the system from headline power alone: connector temperature rise depends on contact resistance, cable construction, ambient temperature, duty cycle, cooling flow, and control limits.

Charging capabilities and certification requirements evolve by region. Confirm the latest edition of the applicable standard and the vehicle/charger implementation before design release.

6. GSConn High-Power EV Connectors

Series	Type	Rating	Features
EV-DC-250	DC fast (CCS-style)	250A, 1000V	Liquid cooling option
EV-DC-500	DC fast (high-power)	500A, 1000V	Liquid cooled, temp sensor
EV-AC-32	AC charging (Type 2 style)	32A, 230V	IEC 62196, locking
EV-BMS-PWR	BMS power interconnect	50–150A	Sealed, vibration-proof

GSConn high-power EV connectors cover DC fast charging (up to 500A, 1000V) and AC charging (Type 2 compatible). Liquid-cooled options for >350kW stations, silver-plated contacts, and integrated temperature sensing. Compliance support for IEC 62196 and UL 2251.