EVSE (Part 1)

EVSE stands for Electric Vehicle Supply Equipment.

The term EVSE has been in use for a long time, and the 1996 NEC and California Article 625 defined (PDF) EVSE as:
The conductors, including the ungrounded, grounded, and equipment grounding conductors, the electric vehicle connectors, attachment plugs, and all other fittings, devices, power outlets or apparatuses installed specifically for the purpose of delivering energy from the premises wiring to the electric vehicle.

This two-way communication ensures that the current passed to the vehicle is both below the limits of the wall charger itself and below the limits of what the car can receive. There are additional safety features such as a safety lock-out that does not allow current to flow from the wall charger until the plug is physically inserted into the car. While this new standard does result in additional cost to the consumer (versus just plugging into any 240 volt socket), their are benefits besides just safety. Adjusting the vehicle’s on-board charger to make sure it doesn’t exceed the power limits of the circuit it is plugged into is no longer required with EVSE. This is an important simplification to the charging process, and should help facilitate adoption of EVs in the future for people who could care less what current, voltage or wattage are.

There are three modes available for charging batteries:

  • AC Level 1: 120 VAC, 1 phase, 12 A, circuit breaker rating: 15 A, charging time 22 h
  • AC Level 2: 208 to 240 VAC, 1 phase, 32 A, circuit breaker rating: 40 A, charging time 8 h
  • DC Charging: 600 VDC, max current: 400 A, charging time 30 mn
  • Here is an illustration of the j1772 inlet:

    And there is an illustration of the j1772 plug:

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