Electric Vehicle Supply Equipment (EVSE)

1. Visit the site with OS-Clean Transportation Unit Project Director and Engineer of Record to determine number of current and proposed fleet vehicles, existing electrical capacity and other site conditions.
2. Site Assessment Report will be completed providing site conditions and recommendations for an EVSE project.

Client will work with Clean Transportation Unit to determine the number and the type of EVSEs needed at a site. Collaboratively, client and OS will determine the optimal location for EVSE placement. Based upon the available power at the site, OS will determine the electrical upgrades needed to install EV infrastructure. Based upon the site assessment, the number of EVSE requested, and the availability of power at the site, OS will develop a preliminary cost estimate.  

OS Clean Transportation Unit will advise clients on the availability of general fund dollars and other funding opportunities. OS can fund and manage EVSE projects from start to finish at state-owned facilities and can purchase chargers at state leased facilities.

Once funding is secured, OS will develop preliminary drawings, working drawings, project manual, and contract documents for contract solicitation. OS will monitor the contracting process through contract award and execution. OS will handle the construction management of the project through project completion.

OS will advise clients on EV pricing, operation, and maintenance of EVSEs. OS will advise clients on the availability of network management services.

Level 1 AC is the most abundant type of charging connection, since it can be done through a common 120 volt AC three prong convenience outlet. Most vehicles are equipped with a portable EVSE that can be used nearly anywhere electrical service is available. However, it has the slowest charge rate at approximately 4 to 6 miles per hour. Higher amperage allows for a faster charge rate. Level 1 EVSE may be portable or permanently wired to the electrical service. A 15 amp breaker is the minimum required however a 20 amp breaker or higher is generally recommended, depending on the model of EVSE used. Note that the electrical code requires the breaker to be down-rated when used in a continuous mode such as EVSE. A dedicated circuit is also recommended since multiple loads may overload the circuit and the EVSE could cause interference with other electrical devices.

This type of charging connection is the most prevalent for charging EV since it is generally twice as fast as Level 1 and provides 10 to 20 miles of range per hour of charging. It requires 240V service which is readily available in many buildings and homes but may not be available at some surface lots and smaller facilities. Other voltages such as 208V or 277V can be transformed to 240V with additional expense. Amperage will vary depending on EVSE used and the service available varying from 40 to 100 amps. Again, higher amperage allows for a faster charge rate, provided the vehicle is designed to accept higher amperage. Level 2 EVSE are nearly always hard-wired to the electrical portal. However, some EVSE manufacturers market a Level 2 portable device with a NEMA 14-50 plug that can be used in a common clothes dryer or recreational vehicle outlet, which may not meet local electrical codes.

This type of charging connection can raise the rate of charge to approximately 75% to 80% in as little as 20 to 30 minutes, depending on battery size. This type of EVSE uses an off-board charger that transforms AC power to DC and bypasses the on-board charger. Generally, 208V three-phase or 480V service is required for this type of charging and may not be commonly available. In many cases, a new separate service will need to be installed by the local utility. A major issue with DC fast charging is the lack of uniform standards in regard to connectors as discussed below. Level 3 DC units and infrastructure cost significantly more and are currently used in only specialized situations or major transportation corridors. With the significant advantages of fast charging and the rapid adoption of electric vehicles, this level of charging will likely become more widely available in the next few years. Vehicle owners should consult the owner’s manuals of their EV since some battery manufacturers suggest that repeated Level 3 charging could shorten battery life.