EV charging connector types

A home wallbox and a highway fast charger can look like the same thing from a few steps away – a plug on the end of a black cable. Underneath, they are doing very different jobs. The connector on a 7 kW AC wallbox lives a very different life from the connector on a 300 kW DC station.   The difference between AC and DC charging is not only the time it takes to fill a battery. It decides where the power electronics sit in the system, how much current runs through the contacts, how hot everything gets, and how heavy and stiff the cable has to be.   If you need a refresher on what the different charging levels mean in daily life, this overview of EV charging levels is a good starting point.     Where AC and DC sit between grid and battery On an AC charger, the grid supplies AC and the car does the heavy electrical work. The wallbox or socket delivers AC power, while the on-board charger (OBC) inside the vehicle converts it to DC for the battery. Power is capped by the OBC rating, typically somewhere between 3.7 and 22 kW for light-duty vehicles. In this arrangement, the connector and cable see moderate current and modest heat, because the hottest and most complex parts live inside the car.   On a DC fast charger, the hard work moves out of the vehicle. The cabinet converts AC from the grid into high-voltage DC and pushes that DC through the connector and cable directly to the battery bus. Power can easily sit in the 50–400 kW range or higher, so the main contacts and conductors carry much higher current and spend more time closer to their thermal limits.   In practical terms: AC keeps the toughest work inside the car, DC pushes that stress into the plug and the cable.     AC vs DC AC: power limited by the vehicle’s OBC, lower current in the cable, smaller heat load at the connector. DC: power limited by the station and battery, high current in the cable, much more heat to manage at the connector. The same vehicle can be easy on an AC plug and very demanding on a DC fast connector.     How AC and DC affect connector internals Higher voltage and current do not just change the rating on the label. They force the connector designer to make different choices in insulation, contact geometry and pin layout.   Power levels, insulation and contact design Light-duty AC charging usually runs at familiar mains-level voltages. DC fast systems sit on high-voltage battery platforms such as 400 V or 800 V. As voltage rises, the connector has to give those voltages more room. Creepage and clearance distances inside the housing get longer, insulation materials need higher performance, and the internal geometry must avoid sharp edges and dirt traps that could weaken insulation over time. The current profile changes just as much. In home and workplace AC use, connectors tend to carry tens of amps per phase. On a DC fast connector, each main contact may be asked to handle several hundred amps. That pushes designers toward larger contact faces on the DC power pins and much tighter control of contact resistance. Spring and blade systems have to keep contact force consistent over many thousands of mating cycles, because a small increase in resistance at high current can quickly turn into heat.   In practice, connector designers focus on three things: Voltage drives creepage, clearance and insulation materials. Current drives contact area, plating quality and spring design. Duty cycle (how often it is used) drives how much safety margin is built into all of the above.   Pin layout and functions Both AC and DC connectors combine power and signal pins, but they do it in different proportions. An AC connector for home or workplace use usually carries one or three line conductors, a neutral, a protective earth, and a small set of control pins for pilot signalling and proximity detection. It has enough intelligence to agree basic charging parameters and make sure the plug is seated before power flows. A DC fast connector still carries protective earth, but the main current now runs through large DC+ and DC– pins instead of lines and neutral. Around those big pins sits a richer set of low-voltage contacts. Pilot and proximity signals are still there, but high-power DC often adds communication lines and, in many designs, dedicated temperature sensing to keep an eye on the hottest parts of the connector.   Seen side by side: AC connectors carry modest power pins and a simple control pair. DC fast connectors carry very large power pins surrounded by more signal and sensing pins. As power increases, both the size of the main pins and the number of signal pins tend to grow.     Connector architectures for AC and DC Different standards solve the “AC + DC” question with different mechanical strategies.   One group of systems uses AC-only connectors. These are the inlets you see on cars that take AC at home, at work and at destination chargers. Housings are compact, handles are light, and internal layouts are straightforward. The design is tuned for comfortable daily use and a long service life at modest power.   Combo-style designs take another route. They combine an AC interface with added DC power pins in a single vehicle inlet, so one socket on the car accepts both AC and DC plugs. This reduces the number of openings that need to be cut into the bodywork and gives drivers one clear target when they walk up with a cable. The price is a larger, more complex inlet and tighter thermal design around the DC pins.   Other architectures stay away from combo inlets. Some standards keep AC and DC completely separate so each can be optimised for its own job: AC plugs stay small and light, DC plugs can become as large and robust as they need to be. Newer compact connector families push in the opposite direction and try to carry both AC and DC through a single small shell. That saves space and simplifies the interface, but it raises the bar on pin reuse, insulation design and cooling strategy.     Cables and heat: why DC looks and feels different Conductor size, weight and handling Moving a few kilowatts of AC into a car overnight does not need huge copper cross-sections. The conductors can stay moderate in size, which keeps the cable light enough to lift easily and flexible enough to coil neatly in a corner of a garage.   Moving hundreds of kilowatts of DC in a short stop is a different problem. To keep resistive losses and temperature rise under control, the conductors need far more copper. More copper means more mass, and that mass makes the cable heavier and stiffer. Extra stiffness shows up every time someone tries to bend the lead around a tight parking bay or over a kerb, and extra weight shows up at the strain-relief points where the cable enters the handle or the cabinet.   In practice: Higher DC power → thicker copper cores → heavier, stiffer cable. Heavier cable → more load on strain reliefs and terminations. AC cables can be tuned around comfort; DC cables start from thermal limits and work backwards.   AC charging cables are tuned for daily life. They are meant to be picked up with one hand, snaked between cars in a tight driveway, and coiled without a struggle when the car is done charging. DC fast charging cables have to live with a harder balance. They must carry very high current yet still bend enough that drivers of different strength and height can position the connector without feeling like they are wrestling industrial equipment. The minimum bend radius is chosen to protect the conductors and insulation, but it still needs to work with real-world layouts on charging sites.     Outer jacket, durability and liquid-cooled cables Public sites are tough on cables. Sunlight, rain, dust and road grime are routine. On top of that, leads are dropped on concrete, dragged over sharp edges and sometimes pinched or rolled over by vehicles. To survive that kind of treatment for years, DC cables tend to use thicker, tougher outer jackets. Strain reliefs are reinforced and terminations are built to absorb twisting and pulling without transferring all of that stress directly into the conductors.   Cables at home live in a gentler environment, but they still need to cope with abrasion, dirt and seasonal temperatures for the life of the charger. Their jackets can therefore lean more toward flexibility and appearance as long as basic robustness is covered.   At the top end of DC power, adding copper and relying on natural cooling eventually stops being practical. The cable would have to be so thick and heavy that many users could barely move it, and fixed supports would become mandatory at every bay. Liquid-cooled DC cables solve that by adding a cooling circuit close to the power conductors. Coolant flows near the cores, carrying heat away so the same outer diameter can move more current without runaway temperature rise. The trade-off is extra design work: the coolant path has to stay sealed and reliable for many years, leaks may need to be detected and monitored, and hoses and sensors must be routed in a way that keeps the assembly flexible enough to use.   This is why an AC cable can stay slim and soft, while very high-power DC cables tend to look thicker, more layered and, in some cases, carry visible cooling interfaces.     How to choose connectors and cables for your site Different charging sites put different weight on power, comfort, durability and cost. A small home wallbox and a bus depot may both be “EV charging projects”, but they sit in very different corners of the design space. Application Power priority Handling / comfort Durability focus Typical connector / cable traits Home AC Low to medium Very high Medium, long life in mild environment Compact plugs, slim flexible cables Destination / workplace AC Medium High Medium to high Slightly tougher housings, clear latch feedback Public DC fast charging Very high Medium Very high, outdoor abuse Larger plugs, thick or liquid-cooled cables, rugged Fleet depots / yards High to very high Medium Very high, many plug-ins per day Robust connectors, high-duty cables, easy service Home AC sites usually treat power as a low to medium priority because overnight dwell time is long. Handling comfort is very important, and durability is about lasting years in a mild environment rather than surviving constant abuse.   Drivers who are deciding between Level 1 and Level 2 at home can use our Level 1 vs Level 2 home charging guide to see how these hardware choices feel in everyday use.   Destination and workplace AC live one step up: more users, more plug-in events, more demand for solid housings and reliable latches.   Public DC fast charging pushes power to the top of the list. Handling comfort is still relevant but naturally limited by size and weight. Durability jumps to a very high priority, because the equipment must live outdoors, see many different users and tolerate occasional misuse. Fleet depots and commercial yards sit between public DC and workplace sites. Power ranges from high to very high, and connectors may be mated and unmated many times per day across multiple shifts. Contact stability, mechanical robustness and ease of service matter as much as headline power.   For a full framework on how fleets combine different charging levels across depots, homes and public sites, see our guide on what level of EV charging fleets really need.   Three simple questions usually point to the right row in the table: How long does each vehicle stay parked here? How many times per day will someone plug in and unplug? How harsh is the environment on cables and connectors over ten years?     Workersbee perspective Turning these principles into real projects means treating connector and cable choices as part of the power and site design, not as a cosmetic afterthought. The same charging level can demand very different hardware depending on environment and duty cycle.   For home, workplace and depot AC use, Workersbee develops AC connectors and charging cables built around comfortable daily handling and long-term reliability under regional standards. The focus is on predictable behaviour and a pleasant user experience within typical AC power ranges.   For public DC fast charging and high-utilisation depots, Workersbee provides DC fast charging connectors and cables engineered for high current capability, controlled contact resistance and robust mechanical performance, with options prepared for advanced cooling where project requirements call for higher power and tighter thermal margins.