Charging EVs at home safely and reliably

New IEC International Standard covers residential charging

By Morand Fachot

As sales of personal electric vehicles (EVs), and in particular of plug-in EVs, expand rapidly, trust in the safety and reliability of charging equipment components is important for users. Several IEC Technical Committees (TCs) and Subcommittees (SCs) develop International Standards for all components in the EV charging chain. The latest one prepared for residential charging installations has just been published.

The use of IC-CPD
The use of the in-cable and control protection device (IC-CPD)

Long-time involvement

IEC TC 69: Electric road vehicles and electric industrial trucks, has been developing International Standards for EV charging for a long time. The first edition of its IEC 61851-1, Electric vehicle conductive charging system – Part 1: General requirements, was published in 2001, with three other Standards in the series following later. It is working on developing additional Standards in the series.

IEC TC 69 has also recently published an International Standard for wireless power transfer (WPT) for EV charging.

For its part, IEC SC 23H: Plugs, socket-outlets and couplers for industrial and similar applications, and for electric vehicles, has published three International Standards in the IEC 62196 series of Standards for plugs, socket-outlets, vehicle connectors and vehicle inlets for conductive charging of EVs. The first, IEC 62196-1, which covers general requirements, came out in 2003. IEC SC 23H is also working on developing additional Standards in the series.

A new entrant to the development of International Standards for EV charging is IEC SC 23E: Circuit-breakers and similar equipment for household use, which has just published IEC 62752:2016, In-cable control and protection device for mode 2 charging of electric road vehicles (IC-CPD)

Significant Standard

IEC 62752 is a highly significant International Standard as it concerns the safety of EV charging installations for Mode 2, the recharging mode defined for residential charging. According to IEC 61851-1, Mode 2 charging refers to the "connection of an EV to the a.c. supply network (mains) not exceeding 32 A and not exceeding 250 V AC single-phase or 480 V AC three-phase, using standardized single-phase or three-phase socket-outlets [...]"

This is important in view of the growing popularity of plug-in EVs. By mid-September 2015, the global number of plug-in EVs had broken the one million mark, with all-electric EVs accounting for 62% of the total and plug-in hybrid EVs making up the remaining 38%. 

Vital part in the charging chain

The in-cable control and protection device (IC-CPD) is “an assembly of linked parts or components including cables, plug and vehicle connector for supplying electric vehicles in charging mode 2, which performs control functions and safety functions”. These control and safety functions are integrated in appropriate enclosures – function boxes – which form part of the IC-CPD. The function boxes are located in detachable cable assemblies, connectors or plugs that are not part of the fixed installation. 

Comprehensive Standard

In addition to the usual relevant terms and definitions, IEC 62752 covers:

  • the different types of IC-CPD classification, i.e. according to supply, construction, method of connecting the cable(s), protective conductor path and behaviour in case of open conductor
  • the characteristics of IC-CPDs according to rated quantities (rated voltage, rated and residual currents, breaking capacity, etc.) and standard and preferred values (of rated operational voltage and current, breaking capacity)
  • standard conditions for operation in service and for installation
  • requirements for construction and operation, including electrical performance and protection against electric shock, mechanical and electrical endurance and resistance to mechanical shock, impact, abnormal heat and fire, vibration and more
  • comprehensive tests covering all the above conditions and requirements, plus others such as a hot damp test for tropical environments or the capacity of the function box to resist damage if driven over by a vehicle

The very comprehensive scope of IEC 62752 means that users of EV residential charging installations meeting this Standard can be confident that their equipment is safe, reliable and well suited to their needs.

The use of IC-CPD The use of the in-cable and control protection device (IC-CPD)
Types of IC-CPD Types of IC-CPD according to construction and assembly