So you’ve done your research and decided on the electric car you’re going to buy, and you’re ready for the next big step: figuring out what kind of charging station to buy.
The first major thing to consider when getting a charging station is making sure you have a safety-certified charging station and you have the capacity in your electrical panel to install a charging station.
The next consideration will be whether you purchase a hardwired charging station or a plug-in unit.
So, what’s the difference? Let’s start with the plug-in charging stations.
Plug-In EV Charging Stations
A plug-in EV charging station connects to power by inserting the supplied plug into a matching receptacle (outlet). Plug-in units don’t have conduit like hardwired stations, but instead have a high-quality 240V supply cord that is 12 inches in length. This measurement includes the plug itself and is the longest plug length allowed per National Electric Code.
Before you purchase a plug-in model there are few things to consider about plug and outlet safety.
For personal safety, the circuit breaker MUST be turned off prior to plugging in AND/OR unplugging 240V appliances (including EVSE).
Residential 240 Volt plugs are specifically designed for occasional relocation, such as moving from one home to another. Most outlets are not rated for consistent plugging and unplugging.
A dedicated NEMA receptacle (outlet) is highly recommended. NEMA outlets wear out over time particularly when repeated insertion and removal of NEMA plugs occur. It is recommended that plug-in EVSE remain plugged in.
Check the receptacle to be sure it is not worn. A worn receptacle can cause the plug connection to overheat and become a fire hazard. Do not use a plug that gets excessively hot.
Have an electrician verify all wiring to the outlet is correct and in compliance with local code requirements before connecting the EVSE.
Do not use an EVSE with an extension cord or wall plug adapter. Plug the EV charger directly into the receptacle.
Ensure that the EVSE is mounted to the wall or placed on a support so it does not hang from the receptacle. Receptacles are not designed to support the weight of the EVSE.
Hardwired EV Charging Stations
A hardwired station has three feet of flexible conduit coming from the top or bottom of the station (depending on the model) and service wires that come out of the conduit about six inches for easy installation into a junction box.
When it comes to installation, hardwired units are typically more permanent and are always recommended for outdoor installations as hardwiring the appliance provides a better and more weather resistant connection to power. They can be moved, but you’d probably need to have an electrician come out to uninstall and then reinstall the unit at your new location. With a hardwired station the supply power wires from the station will be connected directly to the power wires coming from the electrical panel (circuit breaker).
When installing a plug-in charging station outdoors you would typically be required by electrical code to have a “While-in-Use” weatherproof Outlet Cover installed over the 240V outlet. These covers allow for the 240V supply plug to enter from the bottom which will require the 12 inch supply plug to make a 180 degree bend if the supply plug comes from the bottom of the unit (varies by model).
With a hardwired charging station you generally do not need to have a GFCI circuit breaker in place whereas you would be required to have this for any 240V outlet used for an electric vehicle charging station per National Electric Code requirements.
Level 2 (240V) charging stations are high power, continuous use devices and hardwiring will provide the best connection to power. This is consistent with other outdoor high power continuous use devices such as HVAC equipment, sprinklers, etc.
Using a GFCI breaker to supply a charging station can result in nuisance tripping of the breaker during charging. The trip threshold for a standard U.S. GFCI breaker is 5mA which is relatively low for electric vehicle charging. For comparison, charging stations have 20mA GFCI protection built into them. At the 5mA trip threshold you may experience nuisance tripping of the circuit breaker during charging due to noise on the line generated by the vehicle.
Give us a call at Cathey Electrical Services, and we will be happy to talk you through your decision!