EV Infrastructure: Residential Installations
More and more people are getting electric vehicles and having the chargers installed in their homes. As an electrician, here’s some basic information on what an Electric Vehicle Charger install is and successful steps on how to do smooth installs.
First, what you are installing is not the charger. The charger is the port that is internal to the electric vehicle. Electricians install the Electric Vehicle Supply Equipment (EVSE) in the home. Article 625 of the NEC titled Electric Vehicle Charging System covers the minimum safety requirements for installing the EVSE.
There are two types of chargers being installed in homes today: Level 1 and Level 2. Level 1 chargers are 120V/20A chargers, meant to be plugged into any 120V receptacle. Level 2 chargers require 240V and at a minimum a 40A plug to install. Most manufacturers recommend doing hard-wire installation instead of the plug-in. A hard-wired install is normally considered Fixed in Place by the NEC while a plug-in is Fastened in Place (Article 625.2). EVSE can be installed outdoors (most EVSE is waterproof) on a pedestal or wall-mounted inside, mainly in garages.
Hard-wired Level 2 chargers are the typical install nowadays. There are three loads these chargers can accept: 32A, 40A, and 48A. The NEC defines EVSE as a continuous load, so common circuit breaker sizes for chargers are 40A, 50A, and 60A. This sample Enel Installation page helps you understand more about a typical installation.
GFCI protection is required for all EVSE installations where the charger is installed in the garage. Both article 210.8 and article 625.54 of the NEC state this. If you are installing a plug-in charger, you will need a GFCI breaker. If you are doing a hard-wire install, the GFCI is installed in the EVSE. Note there have been complaints of GFCI breakers unexpectedly turning off the EVSE when trying to charge vehicles. You should let customers know about this when deciding whether to do a hard-wire or plug-in install.
Permitting, Inspections, and Incentives for Residential Customers
The way in which the local AHJ or permitting agency defines an EVSE installation will determine what else is required for the install. Some jurisdictions treat the EVSE install as an additional branch circuit added to the home, while others request building plans and load calculations as they treat it more like an unique electrical device. Most Federal and State Incentives for EVSE installs require a permit to be issued for the install.
Bonus: For those of you looking to see the internal guts of an EVSE, check out EEVBlog.