Electric Vehicle Supply Equipment (EVSE)

Section 15, Part 1, SP 30:2023 sets the requirements for RCDs protecting electric vehicle supply equipment.

What type of RCD should you use?

Section 15, Part 3, SP 30:2023 (Indian adoption of IEC 60364-7-722:2018) specifies the requirements for electrical installations incorporating electric vehicle supply equipment (EVSE).

Cl. 4.2.11.3.3 Requires each AC connecting point is required to be protected individually by an RCD with a rated residual operating current not exceeding 30mA.

Cl. 5.3.2.2.101 Requires each RCD selected in accordance with Cl. 4.2.11.3.3 to be conform to at least the requirements of type A RCDs. Type AC RCDs are strictly prohibited for use in EVSE applications. This clause further requires that if the socket-outlet or vehicle connector conforms to the IS 17017 series or IEC 62196 series, the RCD selected shall either be:

Type B conforming to IEC 62423 or IS/IEC 60947-2 OR
Type A conforming to the IS 12640 series (IEC 61008 or IEC 61009) or IS/IEC 60947-2 in addition to a residual direct current detection device (RDC-DD) conforming to IEC 62955 OR
Type F conforming to IEC 62423 in addition to a residual direct current detection device conforming to IEC 62955

Virtually all EVSE units, with the exception of DC "fast chargers" (covered by mode 4- further explained here) use socket-outlets or vehicle connectors conforming to the IS 17017 series or IEC 62196 series, requiring all these EVSE to be protected by either a type B RCD OR a type A/F RCD in addition to an RDC-DD.

Requirements for RCDs according to the charging mode

IS 17017-1:2018 (Indian adoption of IEC 61851-1:2017) specifies four types of charging modes used by Electric Vehicle Supply Equipment (EVSE). Irrespective of charging mode, all EVSE units are required to be protected by an RCD meeting the requirements of at least type A with a rated residual operating current less than 30mA.

Mode 1 (used by scooters, bikes etc.): Method for the connection of an EV to a standard socket-outlet of an AC supply, utilising a cable and plug, both of which are not fitted with any supplementary pilot or auxiliary contacts. The maximum current permitted under mode 1 is 16A. This mode of charging is banned in several countries, including the United States, Israel and the United Kingdom. While not banned in India, most commercially available EV cars do not support Mode 1 charging.

Mode 2 (portable EVSE units supplied with cars): Method for the connection of an EV to a standard socket-outlet of an AC supply, utilising an AC EV supply equipment with a cable and plug, with a control pilot function and system for protection against electric shock placed between the standard plug and the EV. The maximum current permitted under mode 2 is 32A. This utilises an IS 1293 or IS/IEC 60309 series plug and socket. This mode of charging is used by portable EVSE equipment supplied with electric vehicles. In this mode, the EV is supplied by AC, with the AC to DC conversion happening within the EV on its "on-board charger". Virtually all these units have a socket-outlet or vehicle connector conforming to the IS 17017 series or the IEC 62196 series and are required to be protected by either a type B RCD OR a type A/F RCD in addition to an RDC-DD.

Mode 3 (fixed AC EVSE units): Method for the connection of an EV to a AC EV supply equipment permanently connected to an AC supply network with a control pilot function that extends from the AC EV supply equipment to the EV. EV supply equipment intended for mode 3 charging is required to have a protective earthing conductor to the EV socket and/or to the vehicle connector. This mode of charging iis used by fixed EVSE units in public and private areas such as homes, offices and factories. In this mode, the EV AC, with the AC to DC conversion happening within the EV on its "on-board charger". Virtually all these units have a socket-outlet or vehicle connector conforming to the IS 17017 series or the IEC 62196 series and are required to be protected by either a type B RCD OR a type A/F RCD in addition to an RDC-DD.

Mode 4 (fixed DC "fast chargers"): Method for the connection of an EV to an AC or DC supply network utilising a DC EV supply equipment, with a control pilot function that extends from the DC EV supply equipment to the EV. EV supply equipment intended for mode 4 charging is required to have a protective earthing conductor or protective connector to the vehicle connector. This mode of charging is utilised by dedicated DC "fast chargers" rated upto 350kW. This is also the only mode of charging that supplies the EV with DC, as the AC to DC conversion happens within the EVSE, and not within the EV "on-board charger". In most cases, a type B RCD is required- consultation with the manufacturer of mode 4 EVSE unit is required otherwise