Certasun Guide to EV Charging Equipment

If you are considering buying an electric vehicle — or even if you already have one — you may be considering adding some type of home charging equipment. However, the choices are not necessarily straightforward — especially if you aren’t an electrician or electrical engineer. Let’s take a look at what you need to know to make a smart choice. First, we’ll go over some basic terminology. Second, we’ll talk about your equipment choices, breaking that down into choices for Tesla owners and choices for owners of other EVs.

EV Equipment Terminology

Understanding a few key terms can make shopping for EV charging equipment less mysterious and enable you to have a more effective conversation with an electrician:

EV Chargers and EV Service Equipment. Industry insiders will tell you that all electric vehicles include an on-board charger.  Vehicle manufacturers don’t let just anyone control the flow of energy into their batteries.

So what are these other boxes people want you to buy for your garage? Technically, they are called Electric Vehicle Supply Equipment, or EVSE. We won’t begrudge you for calling them chargers, though. What they do is make sure no power flows unless the charging plug is physically inserted into a vehicle, that the home does not deliver more energy than the vehicle can safely accept, and that the vehicle does not draw more than the home can safely provide.

120 Volt and 240 Volt circuits. Volts measure how hard electricity is pushing through a circuit. Almost all U.S. homes have 240V service, but most circuits use only half of this and thus operate at 120V. A few specialty circuits, such as those for air conditioning, electric dryers and ovens, and EV chargers, operate at 240V.

Level 1 and Level 2. Level 1 EV service equipment operates at 120V. Level 2 equipment operates at 240V. As you might imagine, Level 2 equipment will charge your vehicle more quickly.

Amps. Amps measure electrical current — how much electricity is flowing.  A 20A circuit can have up to 20A flowing through it, but typically has less at any given moment.  The maximum amount of power a circuit can deliver is its voltage multiplied by its amperage. 

All Level 2 equipment operates at 240V, but different models and configurations have different levels of maximum current.  For example, one 240V charger may operate at a maximum of 32A and another at 48A. A 48A system will charge your vehicle more quickly than a 32A system if your vehicle is also designed to use that much current. An 48A system connected to a vehicle than can only draw 32A will not charge a battery more quickly.

SAE J1772 Connector. This is a standardized connector type used by all passenger EVs in the United States except Teslas.  Any charger you buy from anyone but Tesla will have a J1772 connector for the vehicle. Teslas use a proprietary connector, but you can buy a small adapter from Tesla that will allow you to use a J1772 connector.

NEMA 5-15, 14-50, and 6-50 Receptacles. These are the official names of different types of outlets used in households.  NEMA 5-15 is the name of the nearly universal 3-prong, 120V outlet.  NEMA 14-50 is the most common 240V outlet used with car chargers that aren’t hardwired, although some use a 6-50 outlet.

NEMA 14-50 Receptacle
(240V)