Zero Emission Vehicle

EVSE Project Workflow

    1. Determine the number of current and proposed fleet electrical vehicles (EVs).
    2. Determine workplace parking stalls.
      1. Multiply the workplace parking stalls by 5%.
        1. Multiply the result by 75% for calculating the needed Level 1 ports.
        2. Multiply the result by 25% for calculating the needed Level 2 ports.
    3. Sum the number of Fleet and Workplace ports needed to meet a facility’s needs.
  1. Please refer to this training guide for completing the Cruise request.

  2. Client will work with Transportation Program 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 power of available of 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.  

  3. OS will advise the clients on the availability of outside/third party funding opportunities. For the difference between project costs and outside/third party funding, OS will work with the clients on securing State funding.

  4. 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.

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

Types of EVSE Chargers:

  1. 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.

  2. 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.

  3. 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.

The currently available light-duty vehicles and Levels 1 & 2 EVSE marketed in the US use the standardized SAE J1772-2009 round coupler and inlet which offer significant levels of safety and convenience. This standard should be used in most instances. This type of coupler is designed specifically for vehicles, prevents inadvertent disconnection, has an interlock device that prevents vehicle start-up and has a first-in/last-out ground connection. For safety reasons, the cord and coupler are not energized until it is mated with the inlet and the EVSE communicates with the vehicle’s charger.

Level 3 DC fast charging doesn’t currently have a universally adopted coupler which is a source of confusion. Some vehicles such as the Nissan Leaf, Mitsubishi i MiEV and the future Subaru model use the Japanese developed trade name CHADdeMO coupler which is somewhat larger than the J1772 device. The vehicle must also be specifically equipped for fast charging which is generally an option at added expense.

Most American manufacturers will be using the newly developed SAE J1772-2009 Combo coupler approved by SAE in the fall of 2012. This type of connector is not common but is planned to be widely used in future models. It is a variant of the standard J1772-2009 coupler with two extra pins for Level 3 fast charging as well as Levels 1 & 2. The regular J1772-2009 coupler can also be used with vehicles equipped with the Combo coupler.


Jennifer Brennan, Transportation Program Manager

Department of General Services
Office of Sustainability

707 Third Street
West Sacramento, CA 95605

Contact Information: 

(916) 376-3863