Key Considerations for Installing Electric Vehicle Charging Infrastructure
As electric vehicle (EV) use grows, so does the demand for charging infrastructure across residential, commercial, and industrial settings. One of the critical steps in installing electric vehicle supply equipment (EVSE) is conducting a site assessment, typically performed by qualified electrical contractors. This article provides essential guidance for site surveys and the installation of EVSE, highlighting crucial elements to consider.
Site Assessment Essentials
The first step in the assessment is determining if the power source or service is adequate to support the new load. The capacity of the source must be sufficient not only for the EVSE but for all connected loads. This part of the survey often involves inspecting the service or feeder panelboard to verify existing loads. For smaller services, a load calculation may be necessary to ensure capacity. Given the continuous nature of EVSE loads—defined by Article 100 as a load where the maximum current is expected for 3 hours or more—appropriate sizing of branch circuit conductors and overcurrent protective devices is crucial (see NEC Sections 625.41 and 42).
Another critical aspect is the requirement for a dedicated branch circuit for EVSE installations. According to Section 625.40 of the NEC, “each outlet installed for the purpose of charging electric vehicles shall be supplied by an individual branch circuit. Each circuit shall have no other outlets.” This requirement is particularly clear for Level 2 and fast-charging equipment, but even for Level 1 EVSE (125V, portable plug-in type), considerations about the load profile and potential circuit capacity are necessary.
Installation Requirements
Installation requirements for EVSE vary by manufacturer. It is vital to follow all manufacturer recommendations and comply with local, state, and federal codes and regulations.
For wall-mounted EVSE, outlets should not exceed 1.2 meters (48 inches) above ground. Outdoor free-standing EVSE should have at least 600 millimeters (24 inches) of clearance on all sides and be protected by bollards, curbs, or wheel stops.
EVSE installations require a disconnecting means accessible from the equipment for circuits rated more than 60A or over 150V to ground, as per NEC requirements. The disconnecting means must be lockable in the open position.
Receptacles for cord-and-plug connected EVSE should be within 6 feet of the fixed equipment to prevent damage to the flexible cord. Proper grounding, as specified by the manufacturer, standard practices, and NEC requirements, is essential. Improper grounding can cause issues at startup and over the long term. An equipment grounding conductor should be provided as per Section 250.118, and noncurrent-carrying EVSE components should be bonded to the grounding conductor.
For comprehensive EVSE installation and maintenance guidelines, refer to ANSI-NECA 413, Standard for Installing and Maintaining Electric Vehicle Supply Equipment (EVSE), which complements the NEC by addressing quality and workmanship standards.
