November 29, 2023

Electrical Compatibility and Safety Considerations for EV Charging


6 Min. Read

Safe and efficient EV charging stations are a key element of electrification, especially are more electric vehicles hit the market and the roads.

But how do electric vehicle charging stations work, and why does EV charger installation require additional safety measures, higher-graded materials, and a licensed electrician with additional training and certifications? When it comes to installing an EV charger at-home, why is a dryer outlet not recommended to plug in your EV charging station, and what makes EV charging different from any other appliance in your home?

In this article we take a closer look at the technology that powers EV charging and discuss important safety considerations that make EV charging unlike anything else in your home.

How Electric Vehicle Charging Stations Work

The number of charging ports across the country has almost doubled over the past three years, contributing to higher rates of EV adoption across the U.S. as more drivers feel confident in the accessibility of EV charger and fears around range anxiety are diminished. While the number of charging stations and ports have increased, it’s important to recognize that not all charging ports are the same.

Charging Station Types

Differences in voltage and energy rate can influence the performance and viability of different approaches to EV charging.

With 83% of EV owners charging their vehicles at home, AC charging via Level 1 or Level 2 remains the most widespread method.

Level 1 charging uses a standard 120V outlet and a simple charging cable. It can deliver an energy rate of 1-2 kWh, adding 3-5 miles of range per hour of charge, which translates to an average charging time of over 40 hours for a full battery. This level of charging is a great option for on-the-go emergencies or for people who travel very limited distances, however a majority of EV drivers find this level of EV charging is insufficient for their daily driving needs.

Level 2 charging is a more practical option, with charging times that vary from four to 10 hours. Level 2 charging can either rely on charging equipment plugged into a 240V outlet or hardwired into a dedicated 240V circuit. While certain appliances in your home may use a similar outlet, this connection for an EV charger should be installed by a licensed electrician with EV charger installation experience, as it requires a higher grade of materials designed for continuous use and specific materials must be used to ensure the charger is safely and efficiently installed.

Level 3 charging, or DC Fast Charging, is the fastest charging method, with voltage levels that can range from 400 to 1,000V and energy rates of more than 50 kWh. Due to the high voltage, cost, and electrical infrastructure needed to support this level of EV charger, DC Fast Charging is only available through commercial equipment and can generally only be found in commercial locations. While this level of charger is ideal for travel and quickly topping up your battery, public charging stations experience station connectivity issues, long lines, and often come at a significantly higher cost than charging at home.

Charging Process

There is more to charging an EV than plugging your vehicle in. EVs have built-in electronic components that actively manage power draw to avoid overloading the battery.

With Level 2 and 3 charging, the charging equipment communicates with the vehicle under the IEC 61851 standard. Depending on the vehicle and charging equipment, the connection can monitor the battery level, incorporate residual current device (RCD) protection, or incorporate more advanced elements such as managing bi-directional charging. Smart electrical panels can further optimize the charging process by managing loads.

There is an additional level of communication between systems when using a public charger to charge your EV. The charging equipment can communicate with the power grid thanks to an open protocol like open charge point protocol (OCPP), open charge point interface (OCPI), or open automated demand response (OpenADR) to help forecast electricity needs or adjust pricing.

Ensuring Electrical Compatibility

Although there are eight different types of EV plugs, compatibility isn’t an issue, as many North American automakers have adopted the same standard.

Unless you’re importing an EV not intended for the North American market, your vehicle will come with a J1772 plug for Level 1 and 2 charging and a CHAdeMO or CCS plug for DC Fast Charging. Tesla vehicles are the exception, with a single connector that supports DC Fast Charging as well as AC charging via an adapter.

In the future, a majority of EVs will use the Tesla standard, rebranded as the North American Charging Standard, or NACS. Tesla made this standard public in November 2022, and auto manufacturers behind 75% of EVs on the road have already committed to adopting this standard to streamline and simplify charging an EV in the U.S.

The NACS standard will also make the Tesla Supercharger network available to every EV owner and facilitate the development of a modern charging infrastructure that makes DC charging more widely available.

Safety Considerations for EV Charging Stations

Like with any electrical application, EV charging carries a risk of electrocution and fire. There are standards in place to protect your home and vehicle, and working with a licensed electrician experienced in EV charging installation who uses the correct materials can help ensure your home and vehicle are protected for years to come.

EV charging stations can use more energy than the combined energy needs of every other appliance in your home, so it’s important to recognize that all components of the installation will have a high-powered continuous electrical load for 4-10 hours a day, every day. Investing in high-quality materials can prevent melted components, electrical fires, and other damages.

Can an EV Charging Station Be Plugged Into a Dryer Receptacle?

While a 240V dryer receptacle has the correct voltage to charge an EV with Level 2 charging, there are some major safety and compliance issues to consider. For starters, the dryer’s circuit might not meet the NEC requirements in terms of grounding and emergency power shut-offs. Failing to meet these requirements puts you and your family in danger, and any damages caused by using an incorrect outlet or improperly installed EV charger by a non-licensed electrician will likely not be covered under your homeowner’s insurance.

Additionally, most dryer receptacles use aluminum wiring, which isn’t a good choice for handling the constant high amperage of EV charging applications and can lead to a loss in efficiency over time, as well as melted components and even electrical fires.

Plugging and unplugging your dryer can cause damage to the receptacle and increase your risks of electric shock, which is why hardwiring your EV charger is generally recommended to avoid any issues of parts loosening over time.

Overcurrent and Overvoltage Protection

Bad wiring and electrical overload can result in dangerous conditions and EV chargers need to follow a few safety standards to manage these risks:

  • When using a Level 2 charger plugged into a 240 Volt outlet, you should also use a dedicated GFCI breaker. GFCI protection interrupts power almost instantly in the event of an overload.
  • The NEC code has precise EV charger requirements regarding height, cable management systems, charging cable ratings, interlocks for emergency power shut-off, and more.

Hardwiring isn’t a requirement, but it’s a common practice when installing Level 2 charging equipment for residential use. Instead of plugging charging equipment into a 240V outlet, hardwiring creates a direct connection between the charger and the electrical panel. This approach reduces the risk of failure at the outlet point.

Grounding and Leakage Current

Grounding creates a safe path for current to reach the earth in case of an electrical surge. A qualified electrician can assess your grounding system and make any corrections as needed.

Get Help Choosing the Right EV Charging Solution

How do electric vehicle charging stations work? There is more to charging an EV than simply plugging a vehicle in. EV charging stations use advanced technology to communicate with vehicles and manage risks, but the charging process can vary based on the type of charging station you select.

With over 269,000 successful EV charging installation projects, Qmerit can help you plan for your electrification needs and put you in touch with a qualified installer. Contact Qmerit today to learn more about our EV charging installers to get started.

Author: Greg Sowder

Greg Sowder

President, Qmerit Network