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EVC's & RCD's - a question for Mr Kenyon

Tolly

Mr Kenyon,

If you would be so kind, elsewhere, it has been suggested that an EVC can be supplied from one of the RCCB's in a domestic split-load board. I, however, referred to Section 6.12.3 of the EVC CoP (4th ed) that states that 'Every charging point shall be individually protected by an RCD...', taken to mean that the RCD shall only supply the EVC, on its own cct, nothing else. This was countered, however, with the idea that the CoP statement is ambiguous because it could equally mean that the RCD can simultaneously protect the EVC and other circuits, it's just that it must protect only one EVC along with the other ccts. 

Therefore, what is your intention with the entry in 6.12.3: the RCD connects to only one cct, or it can connect to a number of ccts, but only one cct can have an EVC? 

Thanks

T.

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  • 0
    Tolly said:
    Therefore, what is your intention

    First of all, it is not "my" intention. The requirement comes from international standards, IEC 60364-7-722, and is endorsed by our national Committee, JPEL/64, for inclusion into Section 722 of BS 7671.

    Second, Regulation 722.531.3.101 of BS 7671 has changed slightly in Amendment 2:2022, to help clarify the situation.

    722.531.3.101 Unless supplied by a circuit using the protective measure of electrical separation, each charging point incorporating a socket-outlet or vehicle connector complying with the BS EN 62196 series shall be protected individually by an RCD of Type A, Type F or Type B and having a rated residual operating current not exceeding 30 mA.

    To fully understand this requirement, we first need to understand what is meant my the term "charging point", for which we look in Part 2 (bottom of Page 3 of BS 7671:2018+Amendment 2:2022):

    Electric vehicle charging point. The point where the electric vehicle is connected to the fixed installation.
    NOTE: The charging point is a socket-outlet where the charging cable belongs to the vehicle, or a connector, where the charging cable is a fixed part of the electric vehicle supply equipment.

    So, if there is only one "outlet" in the EVSE (the "charging equipment"), the RCD in Regulation 722.531.3.101 could be:

    (a) In the EVSE itself

    (b) In the distribution board or consumer unit, but dedicated to the circuit supplying the charging point.

    BUT NOT (i.e. not ever) an RCD in a split-load board, as that supplies other circuits, or potentially outlets, whether electric vehicle or otherwise.

    HOWEVER, if the EVSE had two vehicle outlets (as some I have come across), each outlet must be protected individually by an RCD, and therefore the RCDs would be part of the EVSE.


    And the question as to why this is a requirement and why RCDs in split-load boards ought not to be used upstream of EVSE ... well, the EV and the EVSE may both have some "leakage current" and the total of both may be at or around the "limit" discussed in Regulation 531.3.2 (10 mA).

Reply
  • 0
    Tolly said:
    Therefore, what is your intention

    First of all, it is not "my" intention. The requirement comes from international standards, IEC 60364-7-722, and is endorsed by our national Committee, JPEL/64, for inclusion into Section 722 of BS 7671.

    Second, Regulation 722.531.3.101 of BS 7671 has changed slightly in Amendment 2:2022, to help clarify the situation.

    722.531.3.101 Unless supplied by a circuit using the protective measure of electrical separation, each charging point incorporating a socket-outlet or vehicle connector complying with the BS EN 62196 series shall be protected individually by an RCD of Type A, Type F or Type B and having a rated residual operating current not exceeding 30 mA.

    To fully understand this requirement, we first need to understand what is meant my the term "charging point", for which we look in Part 2 (bottom of Page 3 of BS 7671:2018+Amendment 2:2022):

    Electric vehicle charging point. The point where the electric vehicle is connected to the fixed installation.
    NOTE: The charging point is a socket-outlet where the charging cable belongs to the vehicle, or a connector, where the charging cable is a fixed part of the electric vehicle supply equipment.

    So, if there is only one "outlet" in the EVSE (the "charging equipment"), the RCD in Regulation 722.531.3.101 could be:

    (a) In the EVSE itself

    (b) In the distribution board or consumer unit, but dedicated to the circuit supplying the charging point.

    BUT NOT (i.e. not ever) an RCD in a split-load board, as that supplies other circuits, or potentially outlets, whether electric vehicle or otherwise.

    HOWEVER, if the EVSE had two vehicle outlets (as some I have come across), each outlet must be protected individually by an RCD, and therefore the RCDs would be part of the EVSE.


    And the question as to why this is a requirement and why RCDs in split-load boards ought not to be used upstream of EVSE ... well, the EV and the EVSE may both have some "leakage current" and the total of both may be at or around the "limit" discussed in Regulation 531.3.2 (10 mA).

Children
  • 0 in reply to gkenyon

    Thank you for your detailed replies, and sorry about the 'your intention', I was simply thinking about you as the lead author.

    Regards

    T.

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