Electric vehicle charging comes in three broad levels. Level 1 uses an ordinary 120 V receptacle and charges slowly. Level 2 uses a 208 V or 240 V circuit and covers most workplace, residential and fleet charging. DC fast charging delivers much higher power directly to the battery and suits highway sites, retail and some fleets. The right level depends on how long vehicles stay parked and how far they need to go, and each level asks very different things of a building's electrical system.
Where the charging happens
A vehicle's battery stores DC power, but buildings supply AC. Something has to convert AC to DC. The key difference between the levels is where that conversion happens:
- For Level 1 and Level 2, the vehicle has an onboard charger that does the conversion. The equipment on the wall, properly called electric vehicle supply equipment (EVSE), is essentially a smart, safe switch that supplies AC and talks to the car. The vehicle's onboard charger limits how fast it can charge on AC.
- For DC fast charging, the conversion happens in the charging station, which is a large power electronics cabinet. It sends DC directly to the battery, bypassing the onboard charger, so it can deliver much more power.
Level 1
Level 1 uses a standard 120 V receptacle and the cord set that comes with most vehicles. It adds only a small amount of range per hour, but for a vehicle parked overnight or all day that drives a modest distance, that can be enough.
- Good for: residential parking with long dwell times, some workplace parking, plug-in hybrids.
- Electrical impact: low per space, but the receptacle needs its own suitable circuit. Charging draws close to the circuit's continuous limit for hours, which is hard on old wiring and worn receptacles.
- Watch for: extension cords, shared circuits and outdoor receptacles not designed for continuous use.
Level 2
Level 2 uses a dedicated circuit at 208 V (common in commercial and multi-unit buildings with three-phase services) or 240 V (common in houses). Typical units are adjustable and can charge several times faster than Level 1. The actual rate is the lower of what the EVSE provides and what the vehicle's onboard charger accepts.
- Good for: workplaces, condos and apartments, hotels, fleets parked overnight, and most home charging.
- Electrical impact: significant once there are many units. A parkade full of Level 2 chargers at full output adds a large continuous load to the building. This is where EV load management often makes the project possible.
- Note: charging at 208 V gives somewhat less power than at 240 V for the same current, which is worth knowing when comparing product claims.
DC fast charging
DC fast chargers deliver tens to hundreds of kilowatts. How fast a car actually charges depends on the vehicle, battery temperature and state of charge; most vehicles slow down considerably as the battery fills.
- Good for: highway corridors, retail and restaurant sites with short stays, taxi and ride-share hubs, and fleets that need quick turnarounds.
- Electrical impact: large. A single fast charger can need as much capacity as a small commercial building. Multiple units often need a new or upgraded service, sometimes at a higher voltage, and early discussions with the utility. Demand charges can be significant. See demand charges and power factor.
- Watch for: utility lead times, transformer and equipment pads, cooling and noise from the cabinets, and the connector types offered.
Comparing the levels
| Level 1 | Level 2 | DC fast | |
|---|---|---|---|
| Supply | 120 V AC | 208 or 240 V AC | Three-phase AC to the station, DC to the vehicle |
| Speed | Slow | Moderate | Fast, tapering as the battery fills |
| Best where vehicles park | Many hours | A few hours or overnight | Under an hour |
| Building impact per space | Low | Moderate | High |
Connectors
For AC charging in North America, the SAE J1772 connector has long been the standard. For DC fast charging, the Combined Charging System (CCS) has been widely used, and the North American Charging Standard connector, standardized as SAE J3400, is being adopted by many vehicle makers. Adapters exist, but when buying new equipment, check which connectors vehicles using your site will need over the life of the equipment, and whether the units can be updated.
Choosing the right level for a site
The most useful question is how long vehicles stay. A car parked for ten hours at a workplace or overnight at home needs only modest power. A car stopping for twenty minutes at a highway restaurant needs a fast charger. Matching the level to the dwell time avoids paying for capacity nobody uses. Other questions to ask:
- How many vehicles need to charge now, and how many in five or ten years?
- How far do they drive each day?
- Who pays for the electricity, and how will it be billed?
- How much spare capacity does the building's service have?
- Can charging be managed so that not every unit draws full power at once?
- Are there local bylaws or incentive programs that set minimum charging levels?
A typical case
An office building with a surface lot wants to offer charging to employees and visitors. The first instinct is to install a few fast chargers. Looking at how the lot is used changes the plan: employees park for most of the day and visitors for about an hour. The design that results is a larger number of managed Level 2 units for employees, sharing a fixed amount of capacity, and one or two Level 2 spaces with higher output near the entrance for visitors. A fast charger is left as a future option, with conduit installed during the paving work so it can be added without digging up the lot.
Use certified equipment and a permit. Charging equipment should be certified for use in Canada, and the circuits installed by a licensed electrical contractor under permit. The Canadian Electrical Code has specific rules for EV charging circuits.
How ehZee can help
Our EV charging design service starts with how your site is used and what drivers need, then checks capacity, chooses the charging levels and designs the electrical work, including load management where it helps. Drawings for permit are sealed by a licensed professional engineer where required.
Common questions
Is Level 1 charging good enough?
For vehicles that park for long periods and drive modest distances, often yes. It is the least expensive option per space, but each receptacle still needs a proper circuit.
Why does my car charge slower than the charger's rating?
On Level 2, the onboard charger may accept less than the EVSE offers. On DC fast charging, the battery's temperature and state of charge limit the rate, and most vehicles charge more slowly as the battery fills.
Should we install chargers now or just get ready for them?
Many sites do both: install the chargers needed today and make spaces "EV-ready" for later, with capacity planned, conduit installed and panel space reserved. Running conduit during construction or paving is far cheaper than adding it afterwards. Some municipalities now require a share of new parking to be EV-ready.
Does three-phase power matter for Level 2?
Most Level 2 units are single-phase and connect across two phases of a 208 V three-phase system. In larger installations, chargers are spread across the phases so the load stays balanced.