CCS1 (Combo 1) Connector - Pinout, Wiring, DC Fast Charging & Complete Specs
Complete guide to the CCS1 / Combined Charging System 1 connector: Type 1 AC top + DC pins, communication protocols, power levels up to 350 kW, and installation requirements.
CCS1 (Combo 1) Connector. Pinout, Wiring, DC Fast Charging & Complete Specs
CCS1. Combined Charging System 1, also called Combo 1. is the DC fast charging standard for North America. It takes the familiar Type 1 (J1772) connector and adds two large DC power pins below it. That's the "combo" idea: one vehicle inlet that accepts either a Type 1 plug for AC charging or a CCS1 plug for DC fast charging.
Before CCS1 existed, DC fast charging in North America meant CHAdeMO. a completely separate connector. CCS1 eliminated the need for two different inlets on the vehicle. Today, almost every non-Tesla EV in North America uses CCS1 for DC fast charging.
Power delivery goes from 50 kW on older stations up to 350 kW on the latest hardware.
Physical layout
The CCS1 connector has two distinct sections:
- Top section: identical to Type 1 (J1772): L1, N, PE, CP, PP (5 pins)
- Bottom section: two large DC pins: DC+ and DC–
The vehicle inlet has all 7 contacts in a single housing. When you plug in a standard Type 1 connector for AC Level 2 charging, it only mates with the top 5 pins. When you plug in a CCS1 connector, the top section mates with L1/N/PE/CP/PP and the bottom section mates with DC+/DC–.
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The DC pins are significantly larger than the AC pins. they carry hundreds of amps. Each DC pin is roughly 8 mm in diameter with heavy-duty spring contacts rated for high-current continuous operation.
The connector body is large and heavy. A fully loaded CCS1 cable with liquid cooling weighs 3–5 kg. The plug has a release button on top (inherited from J1772) plus an electronic locking mechanism.
Pin assignments
| Pin | Name | Function | Used in AC mode | Used in DC mode |
|---|---|---|---|---|
| L1 | AC Line | Single-phase AC hot conductor | Yes | No |
| N | Neutral | AC return path | Yes | No |
| PE | Protective Earth | Ground / chassis bond | Yes | Yes |
| CP | Control Pilot | Signaling / PLC communication | Yes (PWM) | Yes (PLC) |
| PP | Proximity Pilot | Plug detection / cable rating | Yes | Yes |
| DC+ | DC Positive | High-voltage DC positive | . | Yes |
| DC– | DC Negative | High-voltage DC negative | . | Yes |
During DC charging, L1 and N are not energized. all power flows through DC+ and DC–. But CP and PP are critical: CP carries the high-level communication between charger and vehicle, and PE provides the safety ground reference.
Communication protocols. how CCS1 DC charging works
This is where CCS1 gets more complex than a simple AC plug. DC fast charging requires real-time negotiation between the charger and the vehicle's battery management system (BMS). The charger doesn't just "push power". the vehicle tells the charger exactly what voltage and current it wants, and the charger complies.
Communication stack
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HomePlug Green PHY (HPGP): this is the physical communication layer. It's a form of Power Line Communication (PLC) that uses the CP wire to pass data at up to 10 Mbps. The 1 kHz PWM signal from basic AC charging is replaced by high-frequency PLC signals during DC sessions.
DIN SPEC 70121: the "basic" DC charging protocol. Almost every CCS1 charger supports this. It handles voltage/current negotiation, session management, and safety monitoring. Think of it as "DC charging without the fancy features."
ISO 15118-2: the "smart" protocol. Adds Plug & Charge (automatic authentication via X.509 certificates. no RFID card, no app, just plug in and it bills you), smart charging schedules, and value-added services.
ISO 15118-20: the newest version. Adds bidirectional power transfer (V2G. vehicle to grid), wireless charging support, and improved scheduling.
DC charging sequence
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The CableCheck step is important and CCS-specific. Before any high-voltage DC flows, the charger applies a low test voltage to verify the cable insulation integrity. If the insulation resistance is below spec, the session aborts. This catches damaged cables before they become a safety hazard.
The PreCharge step is also critical. The charger ramps its output voltage to match the battery pack voltage (within ±20V) before closing the main contactors. This prevents the massive inrush current that would occur if you connected a 500V source to a 400V battery with no pre-equalization.
Power levels
| Generation | Max voltage | Max current | Max power | Cable cooling |
|---|---|---|---|---|
| CCS1 v1.0 (2012) | 500V | 200A | 50 kW | Passive (air cooled) |
| CCS1 v1.0 (2014+) | 500V | 200A | 100 kW | Passive |
| CCS1 v2.0 (2017+) | 920V | 200A | 150 kW | Passive |
| CCS1 v2.0 (2019+) | 920V | 500A | 350 kW | Liquid cooled |
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Why 350 kW requires liquid cooling
At 500A, a 5-meter cable with standard copper conductors would generate enormous heat. you'd need 95 mm² cable to keep the temperature rise acceptable, making the cable far too heavy and stiff to handle. Liquid cooling solves this: coolant (typically a glycol-water mix) circulates through channels in the cable, pulling heat away from the conductors. This allows smaller conductor cross-sections (35–50 mm²) while maintaining manageable cable weight and flexibility.
The liquid cooling loop includes:
- A pump unit in the charger cabinet
- Coolant channels integrated into the cable jacket
- Temperature sensors at multiple points along the cable
- A heat exchanger / radiator to reject the heat
Wiring specifications
DC cable (charger to connector)
| Power level | DC+ conductor | DC– conductor | PE conductor | Cable OD |
|---|---|---|---|---|
| 50 kW | 16 mm² Cu | 16 mm² Cu | 6 mm² | ~25 mm |
| 150 kW | 35 mm² Cu | 35 mm² Cu | 10 mm² | ~35 mm |
| 350 kW (liquid) | 35–50 mm² Cu | 35–50 mm² Cu | 10 mm² | ~40 mm (with coolant lines) |
Signaling conductors (inside the cable)
| Conductor | Gauge | Notes |
|---|---|---|
| CP | 0.5–1.0 mm² | Shielded. carries PLC signals at up to 30 MHz |
| PP | 0.5–1.0 mm² | May share shield with CP |
| CP shield | . | Connected to PE at the charger end, floating at vehicle end (or per EMC design) |
Cable length
Standard CCS1 DC cables are 4–5 meters from the charger cabinet to the connector. Some installations go to 6 m. Longer than that and you start fighting voltage drop and cable weight.
The cable is rated for 600V DC minimum (most are rated 1000V for headroom) and must withstand the thermal cycling of repeated fast charge sessions. cold to hot to cold hundreds of thousands of times.
Electrical characteristics
| Parameter | Value |
|---|---|
| DC voltage range | 200–920V (charger output) |
| DC current range | 0–500A |
| Max continuous power | 350 kW |
| Insulation resistance (cable check) | > 100 Ω/V (min 100 kΩ at 1000V) |
| Contact resistance (DC pins) | < 0.2 mΩ at rated current |
| DC pin temperature limit | 90°C (passive) / 70°C (liquid cooled, higher current) |
| CP PLC frequency | 2–30 MHz (HomePlug Green PHY band) |
| Communication latency | < 100 ms (CurrentDemand loop) |
| Emergency shutdown | < 100 ms from signal to contactor open |
| Insertion cycles | 10,000 minimum |
Safety features
CCS1 incorporates multiple safety layers:
-
Insulation monitoring: continuous monitoring during the session. If insulation resistance drops below threshold, the session terminates.
-
Cable check: pre-session insulation test at low voltage.
-
Voltage matching (PreCharge): charger matches battery voltage before contactor close. Maximum allowed difference: ±20V.
-
Contactor welding detection: after session ends and contactors command open, the charger verifies voltage drops to zero. If it doesn't, a contactor is welded shut. the system flags a critical fault.
-
Ground fault detection: separate from insulation monitoring. Monitors for DC ground faults (leakage to chassis).
-
Over-current protection: charger-side current sensors with hardware trip levels independent of software.
-
Emergency stop: physical E-stop button on the charger. Cuts power within 100 ms and signals the vehicle to open its contactors simultaneously.
-
Connector temperature monitoring: thermistors in the connector body near the DC pins. If temperature exceeds limits, the charger reduces current (derating) or shuts down.
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CCS1 vs CHAdeMO. why CCS won in North America
| Feature | CCS1 | CHAdeMO |
|---|---|---|
| AC + DC in one inlet | Yes | No (separate AC plug needed) |
| Communication | PLC on CP wire | CAN bus (separate pins) |
| Max power | 350 kW | 400 kW (spec) / 150 kW (common) |
| Plug & Charge | Yes (ISO 15118) | No (separate authentication) |
| V2G capable | Yes (ISO 15118-20) | Yes (CHAdeMO 2.0) |
| Vehicle inlet size | Smaller (one combo inlet) | Larger (need two inlets) |
| Cable weight | Similar | Similar |
| North America adoption | Nearly universal | Dead (Nissan abandoned in 2022) |
CCS1 won because it's a simpler vehicle-side integration. one inlet instead of two. The combined AC+DC approach means less sheet metal, less wiring harness, and lower manufacturing cost. The ISO 15118 smart charging ecosystem was the final nail.
Compatibility
- Type 1 (J1772) → CCS1 inlet: works natively. Plug your J1772 AC charger into a CCS1 inlet and it charges at AC Level 2. The bottom DC section of the inlet stays empty.
- CCS1 → CCS2: no simple adapter possible. The upper sections are physically different (Type 1 vs Type 2). Some aftermarket adapters exist but are not widely certified.
- CCS1 → NACS: adapters available (or will be) as the industry transitions to NACS/J3400 in North America. Tesla provides CCS1-to-NACS adapters at Supercharger stations.
- CCS1 → CHAdeMO: no adapter. Completely different connector form factor and communication protocol.
Installation requirements
Power supply
A 350 kW CCS1 fast charger needs serious electrical infrastructure:
| Charger power | Utility supply | Transformer | Service panel |
|---|---|---|---|
| 50 kW | 480V 3-phase, 80A | 75 kVA | 100A panel |
| 150 kW | 480V 3-phase, 225A | 225 kVA | 400A panel |
| 350 kW | 480V 3-phase, 500A+ | 500 kVA | 600A+ panel |
Most 350 kW stations are fed by dedicated distribution transformers. The utility connection is usually 12.47 kV or 4.16 kV medium voltage stepped down to 480V.
Site requirements
- Concrete pad: 6" minimum, reinforced. The charger cabinet weighs 500–1500 kg.
- Cable trench: from transformer/panel to charger. Conduit sized for DC bus cables.
- Bollards: crash protection around the charger cabinet. Required by most jurisdictions.
- Drainage: the pad must drain away from the charger. Water pooling + 920V DC is not a scenario you want.
- Network connectivity: cellular (4G/5G) or Ethernet for OCPP communication, payment processing, and remote monitoring.
- Lighting: adequate illumination for safe nighttime use. Most building codes require this.
CCS1 is the backbone of non-Tesla DC fast charging in North America. It's mature, well-supported, and the 350 kW capability handles everything from city commuters to long-haul road trips. The transition to NACS will take years, and CCS1 stations will remain in service for a long time.