EV charging glossary

The vocabulary in this subject is unusually bad, because several terms mean different things depending on who is speaking. "Charger" is the worst offender: it is used for the box on the wall, the cable in the trunk, and the component inside the car, and those are three different objects. Where a term is ambiguous, this glossary says so instead of picking one meaning.

Charger

Colloquially the equipment you plug into the car. Technically the AC-to-DC converter inside the vehicle. When somebody says their car has a 7.2 kW charger they mean the internal one; when they say they bought a charger they mean the external box. Both usages are everywhere and neither is going away.

Charging brick

The EVSE unit in the middle of a portable charging cable — the box between the wall plug and the car connector. Note that the same phrase is used for phone chargers, which is why search volume for it is misleading.

Fast charging

Means DC fast charging to most people, but some marketing uses it for Level 2 against Level 1. If a product plugs into a wall outlet, it is not DC fast charging whatever the listing calls it.

Installation

A licensed electrician adding a circuit, in the sense that matters to a landlord. Plugging in an appliance is not an installation, and being clear about that distinction is most of what makes a request approvable.

EVSE

Electric Vehicle Supply Equipment. The formal name for what everybody calls a charger: the box that communicates with the car, limits current and cuts power on a fault. It does not convert anything.

Onboard charger

The AC-to-DC converter inside the vehicle. Its rating — commonly 7.2, 9.6 or 11.5 kW — sets the ceiling for AC charging regardless of what you plug in.

J1772

The SAE standard AC connector used by most non-Tesla EVs in North America. Larger, with a flat-topped outline and a latch tab on top.

NACS

North American Charging Standard, the connector Tesla developed and the industry is adopting. Smaller and round, and unusually it carries both AC and DC through the same shape.

CCS

Combined Charging System. A J1772 connector with two additional large DC pins beneath it. The upper section works with any J1772 AC equipment.

Splitter switch

A listed device that shares one 240V circuit between two appliances, switching automatically so only one draws at a time. Not the same as a passive Y-adapter, which lets both draw and is the wrong product.

NEMA

National Electrical Manufacturers Association, whose numbering describes plug and receptacle configurations. The first number is the configuration, the second is the amperage: NEMA 14-50 is a 50 amp device.

NEMA 5-15

The ordinary 120V household socket, on a 15 amp circuit. Supports 12 amps of continuous EV charging.

NEMA 14-50

240V, 50 amp, four-wire. Ranges and RV pads. Supports 40 amps continuous — the fastest plug-in charging a renter can normally reach.

NEMA 14-30

240V, 30 amp, four-wire. The modern dryer outlet. Supports 24 amps continuous.

NEMA 10-30

240V, 30 amp, three-wire, with neutral and ground sharing one conductor. The older dryer outlet, still common in pre-1996 housing.

Continuous load

A load running three hours or more. The National Electrical Code limits it to 80% of the circuit rating, which is where every 24-amp and 40-amp figure on this site comes from.

AWG

American Wire Gauge. Smaller numbers mean thicker wire: 10 AWG is heavier than 12, which is heavier than 14. Gauge determines how much current a cable carries without overheating.

kW

Kilowatt — a rate of power. Volts × amps ÷ 1000. It is how fast energy moves, not how much of it there is.

kWh

Kilowatt-hour — an amount of energy. A 7 kW charger running for two hours delivers 14 kWh. Batteries are measured in kWh and electricity is billed in it.

Miles per kWh

Your car's efficiency. Multiply by charging power in kW to get miles of range added per hour. It moves substantially with temperature and driving style.

Level 1

120V AC charging, about 1.4-1.8 kW. An ordinary socket.

Level 2

240V AC charging, roughly 5.8-9.6 kW for a renter depending on the circuit. Needs a 240V outlet but not necessarily an installation.

Level 3 / DC fast charging

The station converts AC to DC and feeds the battery directly, at 50-350 kW. A different technology, with no residential equivalent.

UL 2594

The safety standard for electric vehicle supply equipment. Worth looking for on any charger you buy.

UL 2251 / UL 2252

Standards covering charging couplers and adapters. A published certificate number is checkable in a way that the word 'certified' is not.

IP rating

Ingress protection, as two digits: dust then water. IP66 is dust-tight and resists water jets; IP67 adds temporary immersion. Manufacturers often publish a higher unmated figure and a lower mated one — the mated figure applies while charging.

NEMA enclosure type

A separate rating system from NEMA plug configurations, confusingly using the same body's name. Type 3R covers outdoor rain and sleet; Type 4 adds hose-directed water.

GFCI

Ground-fault circuit interrupter. Required on most outdoor receptacles. Occasionally produces nuisance trips with EVSE that has its own ground-fault detection.

If you came here from a specific page, go back to it. If you came here first: the pillar guide is the place to start, and level 1 vs level 2 is the single most useful page for deciding what you actually need.