Your shiny new electric vehicle is fantastic. You love kicking gas to the curb and sticking it to the man. Your next act of independence from big oil will be to get your at-home charger (technically called an EVSE) up and running so you can charge at a better rate than the 115 V mobile charger offers. Before you start asking other amateurs on the interweb for advice, here is our suggestion. Call an electrician.
If you are not a licensed electrician, you are not qualified to install a new 240 V outlet or hard-wired device in your home. The list of things you don’t know about this project can kill you, burn your house down, or possibly harm a first responder.
What exactly is your goal? To save a couple of hundred dollars? Compared to the cost of ownership of an EV that number is meaningless. Compared to the money on gas you will save (unless you had a hybrid before your EV), the cost of a properly installed hard-wired charger or outlet is meaningless.
Most municipalities require an electrical building permit for the installation of any new EV charger outlet. That signed-off building permit has great value to you. First, it could prevent a fire. Second, it could protect your financial well-being. Third, when you sell your home the home inspector is going to ask if it was inspected. A "no" answer could delay the sale.
If you burn your house down or if someone is harmed by a faulty high-amperage line you installed without a permit, do you think your homeowner’s insurance company is going to pay for repairs or liability claims? Why would they? Why should they?
George Betak is an EV early adopter, EV owner, and George is the guy who started most of the popular EV fan sites on Facebook. We asked George what he thinks of the daily posts asking: “What does the black wire do?” and other silly questions from new EV owners trying to install their own charger and here is what he said: “Penny pinching at its worst. The number of times we would see owners doing their own wiring and proudly showcasing it in front of thousands of people, even though it wasn't up to code, and as if such behavior was some kind of virtue is, quite frankly, shocking.”
Here is a quick rundown of the things that you don’t know and an electrician does.
Line of Sight To Panel Disconnect
If you run a new line to your hard-wired EV charger from your service panel and you cannot see the panel from the charger, do you need a service disconnect? Your electrician knows the answer.
Can the Service Box Accommodate This Addition?
Does your home electrical box have the capacity to accept a new line? Is there room in the panel? Is the panel up to the current code? Do you have current hot-spots from existing arcs that may be a threat? You don’t know. Your electrician will.
Which Breakers? AFCI, GFCI, WTF?
You don’t know which size breakers you need. You don’t even know which type you need. Will the ones you will source from your local home improvement big-box store meet the current code requirement for your specific application? If you have any doubt why would you proceed? An electrician will know the answer. As will the inspector.
The New Dedicated Line
No EV is designed to be charged on a shared line. You probably knew that. But what rules apply to running that new 4-wire line? What cable is required? What conduit? Can you cross a rafter? Your electrician knows the answers in her sleep. Get it wrong and you won’t pass the rough-in inspection. You did schedule the rough-in inspection, right?
If your new line to the charger requires that you exit the building that houses your panel you will be excavating to lay your line. Do you need to call Dig Safe? Do you know the current codes for underground cable placement? Since you are going to the expense to lay a cable under the ground have you considered future upgrades? Are you running an additional 115 V line or low-voltage landscaping lighting line as well since adding one later is such a hassle? Are you leaving in place a pull-through string to enable future lines? Your electrician will know how to do this safely. As will your building inspector.
What NEMA rating do you need for your specific charger installation location? 3R or 4?
The Dryer Socket Mystery
A 240V receptacle properly wired with a 20A breaker can accommodate a plug-in Level 2 EVSE. If your garage has a 240V outlet, perhaps with a NEMA 6-20R, three-wire setup, you may be able to buy an EVSE that plugs in and delivers around 10 miles of range per hour on the charger. If you have any doubts, best to ask your electrician to check it out. Experts we respect suggest that you should only consider EVSEs that are UL Listed.
Please. If you are about to begin living electric, start off with a professionally installed, properly inspected, and approved charger circuit. Why wouldn’t you? You were smart enough to see the value in an EV.
If you are an electrician, please feel free to let us know in the comments below if our terminology is wrong, or if we left anything out. We're not experts on 240-volt wiring requirements and will update the story accordingly.
John Goreham is a long-time New England Motor Press Association member and recovering engineer. John's interest in EVs began in 1990 when he designed the thermal management system for an electric vehicle as part of an academic team. Following his engineering program, John also completed a marketing program at Northeastern University and worked with automotive component manufacturers. In addition to Torque News, John's work has appeared in print in dozens of American newspapers and he provides reviews to many vehicle shopping sites. You can follow John on Twitter, and view his credentials at Linkedin