There are four basic steps in getting your house ready for EV charging:
- Determine the type of charger that will be needed (Level 1 or Level 2).
- Find the right location for the charger (garage, driveway, side of house, curbside on public road).
- Check your homes electrical capacity.
- Schedule installation work.
Once you have decided to get your home EV ready, you need to decide on the type of charging you will need. Residential charging is divided into two types: “Level 1” uses a standard (120v) household outlet and “Level 2” (240v) uses a more powerful heavy duty socket . Level 1 charging is inexpensive since all that is needed is a 120V outlet and a Level 1 charger, (which is essentially a special extension cord that comes with the EV at purchase). Level 2 is more involved since heavy duty wiring, circuit breakers, and a separate EV charger are needed.
How to select the right category of charger?
Level 1 chargers provide 3-5 miles of range per hour of charging and should only be used if you have a plug-in hybrid car[1] , rather than a fully battery electric car. Plug-in hybrids have small batteries and limited electric range and can fully charge using a Level 1 charger overnight. Battery electric cars have large batteries and driving ranges that average over 200 miles, with some models offering a range of over 400 miles. In these cases, the faster Level 2 (10 – 30 miles of range) per hour are needed unless you only drive a few miles per day.
Preparing your house for a Level 1 EV charger.
The first step in this process is to see if you have any outdoor (water protected) outlets installed near where you park your car. This could be an outlet on the wall of your house that you might use for outdoor power tools or other plug in items. You might also have outlets in your garage. Check to see if the outlets are 3 prong style, which are needed for Level 1 EV chargers. See figure 1.
If the outlet is exposed to the elements (rain), then it should have additional features such as a waterproof cover, and a “GFI” circuit. See Figure 2.
If you have either of these outlet types, then there are no additional steps that you need to make for a Level 1 charger. You are EV ready! You can connect your plug-in hybrid and get an instant (though relatively slow) charge right away. For some people, this modest outlet is all that is needed since the number of miles that they travel on a regular basis is limited by the small battery in their car. For other drivers who want to get their house fully EV ready, additional steps (and hardware) are needed.
Preparing your house for a Level 2 (240V) EV charger.
If you are planning on a fully electric car then, except for a few circumstances where you might just drive short distances every day, you will need to get a Level 2, 240 Volt charger. Level 2 chargers are capable of adding 10-30 miles of electric range per hour and can fully charge an EV battery overnight. The planning and installation for this type of charger is more involved, but you will end up with a much more powerful, future proof and useful charger for your EV.
Surveying possible locations for Level 2 charger.
Level 2 chargers can be located either in a garage, outdoors in a driveway, or “curbside” at your house or apartment. When looking for a location for the charger, try to find a spot that is at or near where you park your car, and also someplace that is nearby some existing electricity. For those who have a garage, this is a perfect location. If you don’t have a garage, look for a place that the wiring can be placed, such as the side of your house. If this is not possible, pick a place in the driveway where you could locate a small pole that would hold an electrical outlet.
In some cases, this pole mount system can be used in homes that do not have driveways. To accomplish this, a homeowner would need to find (unmetered) street parking that is adjacent to land owned by the homeowner, then run the electrical underground to the edge of the homeowner’s land so that the charging cord could reach from street parking to the electrical charger or outlet.[2]
Once you have determined the best location, the next step is to choose the electrical hardware. The easiest way to get your house EV ready is by installing a heavy duty electrical outlet. These outlets (called “NEMA 14-50” types) are commonly used for electric dryers, so electricians are very familiar with them. Installing the outlet and not a “hard wired” charger gives you flexibility. Once this outlet is installed, in the future you can simply plug in your charger when you get one, and you can also take your charger with you when you move.
Figure 3, NEMA 14-50, 240V outlet.
Surveying your home’s electrical capacity.
Since Level 2 (but not Level 1) EV chargers draw a considerable amount of power, you will need to ensure that your home’s electrical system is up to the job prior to installing the wiring for the charger. To do this, you should check your main electrical panel. If the box is full and there are no blank spots left for new breakers, then you might need to upgrade your electrical panel while you are having the EV charger wiring installed by the electrician. Older homes that do not have central AC might only have a 100A (amp) electrical panel, while newer homes have 200A panels that would provide more room for an EV charging circuit. The need for an upgrade is not bad news in itself; upgrades are commonly done in older homes and make your home ready for future clean electric heating as well, but they will add cost to your EV wiring installation.
The final step in the process is to find and hire an electrician to complete the installation. To do this you can start some research by talking to friends and neighbors who already have EVs, or you can call your electric utility. Make sure that the electrician is fully licensed and insured, and that he/she is either getting a permit or following electrical code requirements.
[1] Plug in hybrid cars have both gas engines and batteries. Depending on the car model, batteries provide roughly the first 20 miles of range, then the gas engine takes over.
[2] Individual municipality restrictions may apply, consult permitting authorities prior to undertaking this type of work.
