Circuit Requirements, Installation Risks, Average Cost and General Information
J. Fritscher – April 10, 2024
If you’re ready to upgrade to a level 2 EV charger for your electric vehicle, there are a few things you might want to think about. First, and perhaps most importantly, you should make a list of your wants, as well as what you are willing to trade to fulfill those desires.
For example, you may really want a charger that is able to complete a full charge in under six hours, or maybe you’d like to charge two vehicles at once. This constitutes what you’d like to get out of your new charger. Next, you need to determine how much you’d like to invest in your new charger. Keep in mind that your investment should include the charger itself, along with any accessories and electrical upgrades that may be required to power the charger.
We will assume that you have landed here to learn more about the electrical requirements for your new EV charger, so we will skip straight to it, but for those interested in learning more about EV chargers in general, we will also provide those details further in this reading.
The first thing to consider is if your existing electrical service equipment can support your new charger. You may need to simply add a new circuit breaker and branch wiring, or you may need to add a subpanel or even upgrade your entire electrical service including the meter and electrical panel. There may be more than one option depending on your existing installation and the jurisdiction your home is located in. For example, you may already have a 200A meter but only have a 100A electrical panel. In this case, you may be able to install a 200A busway and use it to feed the existing 100A panel and an additional dedicated circuit for a new EV charger. Alternatively, you could add a larger 200A panel as the main service panel and feed the existing 100A panel and a new EV charger circuit from it.
If you’d like to estimate whether your existing panel can support your charger, our article on estimating for new electrical circuits may be helpful to you.
It’s also important to understand that the wiring and circuit breaker must be sized larger than the rating of the EV charger for safety considerations. Current electrical code as of this writing requires that a circuit providing a continuous load, such as an EV charger, must not be loaded beyond 80% of the circuit’s capacity. To simplify this, just multiply the charger’s current rating by 1.25. So, for a 50A charger, the circuit wiring and circuit breaker must be rated for 1.25 * 50A = 62.5A. In this case, the circuit wiring and breaker must be sized to 70A because 70A is the next standard size circuit breaker available.
It is not uncommon to find improperly sized EV charger circuits because they were installed by a handyman, a homeowner, or an electrician doing side-work and the installer was not aware of the proper sizing. We see 48A chargers on 50A circuits all the time because the installer assumed a 50A circuit should support a 48A charger.
As you can see from the picture, undersized circuits can lead to excess heat buildup in the wires and could potentially start an electrical fire.
Another thing to consider is how your new level 2 charger is powered. Is it supplied with a cord and plug to attach to an already installed electrical outlet, or does it need to be hardwired?
Speaking of cords, you’ll want to plan out the location of your new EV charger carefully, as the total length of cord allowed from the charger to the face of the charging plug is limited to 25 feet unless specialty cord management systems are also in place. The ideal placement will provide the most flexibility, such as being able to charge a vehicle if it is parked on either the left or right side of a two-car garage.
Another common mistake made by handymen, homeowners and electricians alike is installing an incorrect receptacle. Of course, we would love to reduce the installation costs by installing one of those $15 NEMA 14-50R receptacles that can be picked up at any local big box store, but the truth is, these have been known to fail when used for EV charging.
One reason these receptacles fail is because they were installed undersized for continuous operation. However, another common failure is due to the number of mate/demate cycles. That is, how many times a plug has been inserted and removed from the receptacle. Unknown to most, the popular NEMA 14-50R receptacles available for under $20 at a big box store are not designed for repeated mate/demate cycles. These receptacles are typically located at an electric range or clothes dryer, where an appliance is plugged into it one time and rarely ever is it unplugged.
Over time, multiple mate/demate cycles can wear out the contacts within the receptacle. This leads to loose connections and arcing between the plug and receptacle, which causes excess heat buildup and can eventually lead to an electrical fire. To reduce the likelihood of this happening at your home, Mountain Electric always recommends installing industrial grade receptacles that are rated for a higher number of mate/demate cycles. This may slightly increase the initial investment required, but it leads to a much safer installation for an effective cost increase of around $50.
Don’t forget, the 2023 National Electrical Code also requires all EV charging receptacles to have ground-fault circuit-interrupters installed. If you have a cord and plug EV charger and your circuit breaker does not have a “Test” function for ground-faults, then your installation is not code compliant.
Finally, an often overlooked piece of gear for your new charging circuit is whole home surge protection. There are several EV charger manufacturers that require surge protection, or their warranty will be voided. Beyond that, however, it is recommended to protect your investment. We’ve all heard horror stories about the cost of new EV batteries being more than 50% of the cost of the vehicle; no point risking damage to yours to save a few bucks. Technically, the National Electrical Code does not require a surge protective device to be installed unless the service equipment is replaced, but we’d still recommend it.
Without surge protection, your battery (and charger) could be damaged due to electrical surges and voltage spikes.
So, what is the typical value of investing in a level 2 EV charger for your home? Well, that can depend on a number of factors including whether your existing service or equipment needs to be updated, if the circuit can be run directly from the existing electrical panel, if additional equipment needs to be installed, how far the EV charger will be located from the existing electrical panel and the final location of the charger and its associated circuit wiring.
That probably wasn’t the answer you were looking for, so let’s dive into the numbers. At a minimum, we can assume that new EV charger may be located within 10-20 feet of an existing electrical panel that has both space and capacity to support a new circuit for the charger.
Level 2 EV chargers come in a wide variety of power options ranging anywhere from 15A to 80A. Keep in mind the 80% rule, so for a 15A charger the circuit wiring and breaker need to be rated for 20A, or for an 80A charger the circuit should be rated for 100A, As you will learn in the paragraphs that follow, the larger the current requirement of a charger, the faster it will be able to charge a vehicle. If you really wanted a charger that can charge a vehicle quickly, you will need a large capacity circuit for a 50A-80A charging system. Also note that for any charger rated at 60A or greater, a separate disconnect switch is required that can be locked in the open position.
Adding a 20A circuit for a 15A EV charger is significantly less involved than adding a 100A circuit for an 80A charger. Both cases are extremes however, and most homeowners find themselves choosing a charger that lies somewhere in between the two aforementioned options.
Depending on your location, on average, a homeowner can expect to invest between $1000 – $3000 with a typical cost somewhere around $2000. This includes the cost of the EV charger ($300 – $1000) and the cost of professional installation and permitting fees. Yes folks, the additional circuit needs to be permitted and inspected by your local authority having jurisdiction, even if the circuit can be added to your existing panel.
Now that we’ve got that out of the way, let’s learn more about level 2 EV chargers in general.
Most electric vehicle manufacturers supply a level 1 EV charger with the purchase of one of their vehicles. This charger allows you to plug in to a standard 120V receptacle to charge your vehicle. These chargers are fairly inefficient, and most owners find themselves wanting to upgrade their charging capabilities.
Enter the level 2 EV charger. Level 2 chargers operate on 240V as opposed to 120V, meaning they can supply more power at lower current ratings and just more power in general. They work by converting AC (alternating current) electricity from your home into DC (direct current) electricity stored by your vehicle’s battery. The conversion takes place within the charger during the charging process. By contrast, a level 3 charger supplies DC current that doesn’t need to be converted during the charging process, resulting in the fastest charging rates possible.
That isn’t to say that level 2 chargers aren’t fast in their own right. In fact, level 2 chargers can charge a vehicle anywhere from 2-13 hours (compared to 10-20 hours for level 1 chargers). A charger with a 19.2kW (80A) output can typically charge a vehicle in 2 – 3 hours, whereas a charger with an output of only 3.6kW (15A charger) may take upwards of 13 hours to fully charge a vehicle.
EV chargers also come with different plug types. If you live in North America, chances are you will need a Type 1 J1772 plug, please reference your vehicle manual to confirm. This connector has 5 pins/sockets arranged in a circular configuration, with two positions on top and three positions on bottom.
Another common plug type in North America is the NACS (North American Charging Standard) which is used to supply AC or DC charging to Tesla model vehicles. This plug also utilizes 5 positions, with two positions in a row on top and three in a row on the bottom, however, the overall shape of the connector is more oblong than circular as compared to a Type 1 plug.
Other types of charging plugs that we will not cover in detail here include the Type 2 Mennekes plug (Europe, Middle East, Australia, Africa) and the GB/T plug (China).
Level 2 chargers can be supplied with a charging cable and plug that are attached to the unit directly, or they can provide a receptacle to plug in a detachable charging cable. It is important to understand which type of charger you are considering as chargers that utilize detachable charging cables are often less expensive but do not include the required charging cord and plug.
In addition to the charging cable, as mentioned previously, some level 2 EV chargers mount directly to the wall and are equipped with a 240V plug that will require a matching 240V receptacle to be installed in the desired charging location. Other chargers may wire directly to the unit and mount to a junction box. It’s important to select the correct type if you already have provisions available.
Finally, there are options for smart chargers that include load shedding capabilities, or models that charge two vehicles at once, an ideal solution for households with more than one electric vehicle. The correct solution for you and your household is as unique as you are.
Adding a level 2 charger will greatly increase your ability to fully utilize your electric vehicle, but it does take a little planning and consideration. We hope that this guide has provided you with the information necessary to make an informed decision on your upcoming EV charger and installation purchase. Mountain Electric is a Certified ChargePoint installer, if you’re located in Fairplay, Denver or in-between we’d be happy to assist you with your EV charging needs.