It should also be noted that compliance with IEC 60364-7-722 makes it mandatory that the different components of the EV charging installation fully comply with the related IEC product standards. For example (not exhaustive):
- EV charging station (modes 3 and 4) shall comply with the appropriate parts of the IEC 61851 series.
- Residual Current Devices (RCDs) shall comply with one of the following standards: IEC 61008-1, IEC 61009-1, IEC 60947-2, or IEC 62423.
- RDC-DD shall comply with IEC 62955
- Overcurrent protective device shall comply with IEC 60947-2, IEC 60947-6-2 or IEC 61009-1 or with the relevant parts of the IEC 60898 series or the IEC 60269 series.
- Where the connecting point is a socket-outlet or a vehicle connector, it shall comply with IEC 60309-1 or IEC 62196-1 (where interchangeability is not required), or IEC 60309-2, IEC 62196-2, IEC 62196-3 or IEC TS 62196-4 (where interchangeability is required), or the national standard for socket-outlets, provided the rated current does not exceed 16 A.
Impact of EV charging on maximum power demand and equipment sizing
As stated in IEC 60364-7-722.311, “It shall be considered that in normal use, each single connecting point is used at its rated current or at the configured maximum charging current of the charging station. The means for configuration of the maximum charging current shall only be made by the use of a key or a tool and only be accessible to skilled or instructed persons.”
The sizing of the circuit supplying one connecting point (mode 1 and 2) or one EV charging station (mode 3 and 4) should be done according to the maximum charging current (or a lower value, providing that configuring this value is not accessible to non-skilled persons).
Fig. EV22 – Examples of common sizing currents for Mode 1, 2, and 3
|Mode 1 & 2||Mode 3|
|Equipment for circuit sizing||Standard socket outlet|
|Maximum current to consider @230 / 400Vac||16A P+N||16A P+N||32A P+N||16A P+N||32A P+N|
IEC 60364-7-722.311 also states that “Since all the connecting points of the installation can be used simultaneously, the diversity factor of the distribution circuit shall be taken as equal to 1 unless a load control is included in the EV supply equipment or installed upstream, or a combination of both.”
The diversity factor to consider for several EV chargers in parallel is equal to 1 unless a Load Management System (LMS) is used to control these EV chargers.
The installation of an LMS to control the EVSE is therefore highly recommended: it prevents oversizing, optimizes the costs of the electrical infrastructure, and reduces operating costs by avoiding power demand peaks. Refer to EV charging- electrical architectures for an example of architecture with and without an LMS, illustrating the optimization gained on the electrical installation. Refer to EV charging – digital architectures for more details about the different variants of LMS, and the additional opportunities that are possible with cloud-based analytics and supervision of EV charging. And check Smart charging perspectives for optimal EV integration for perspectives on smart charging.