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Details of BS7671:2018 Amendment 1 are here.

Alan Capon
Details of Amendment 1 of BS7671:2018 is available here: https://electrical.theiet.org/bs-7671/updates/


Regards,


Alan.
  • 0
    Thanks for the link.

    So, hands up who things a normal 3 phase contactor wired to break LNE meets 543.3.3.101 for the purposes of  'unplugging' the car charger if the mains voltage goes too high or low.


    Clue it is trick question, can we be sure that  protective conductor to be disconnected last and connected first ?

    This requires fitting special contact spacers under the actuator bar, or some cunning redundant contact and delay arrangement .  Late- break relays do exist, but they are not exactly common yet.



  • 0
    This reminds me of Harrison's early chronometers with all their complicated compensating bits and bobs. One simple solution (at least for single-phase domestic) is required.


    If there is the option of completely isolating the supply in the event of a lost neutral, why not apply it to the whole installation and put it at the origin. In fact, given that a lost neutral is the DNO's responsibility, why not make the protective device a mandatory part of the DNO's equipment?
  • Former Community Member
    0 Former Community Member
    A number of countries have "lost neutral" detection incorporated as part of the suppliers equipment.


    Back in the day, when Mandela was still locked up, the ANC used to see theft of electricity(fiddling the meter) and theft of the infrastructure assets (ie nicking copper) as "legitimate political protest"


    As the neutral is usually the lowest conductor on an aerial flight and isn't usually "hot" that would be the prime target for weighing in.


    If you stick something like a 1KOhm resistor in with a rod, and put a DP RCD as part of the cut out, before the PME link, if the neutral goes AWOL, then the whole installation trips Try a Goole for ESKOM lost Neutral Detector


    All totally unnecessary of course - just make the bloody cars and charger double insulated.


    Regards


    OMS
  • 0

    OMS:

    All totally unnecessary of course - just make the bloody cars and charger double insulated.

     



    For years, the chassis of every car has been connected to the battery negative.  Changing that would require a re-design of the whole car's wiring system, and probably a lot more copper as every electrical accessory would now need a negative wire.
  • 0


    For years, the chassis of every car has been connected to the battery negative.  Changing that would require a re-design of the whole car's wiring system, and probably a lot more copper as every electrical accessory would now need a negative wire.



     



    No need for that - it just needs the on-board 'charger' to provide galvanic isolation between the a.c. supply side and the the vehicle's d.c. side - i.e. what's many conventional SMPSU designs give you anyway. The traction side (usually LV rather than ELV) is usually all copper anyway and the 12V side can continue with its single insulation and chassis return as before.



      -  Andy.

  • 0
    Can anyone confirm if this is going to be available on the VitalSource Bookshelf resource with the permission to print without all the copyright watermarks?


    Peter
  • 0
    Hi Peter,


    Yes, if you already have a subscription to a package on VitalSource, Amendment 1 has been added to your package this morning.


    If not, you can download a printable PDF for your own use for £5 here: https://academy.theiet.org/amendment-1-to-bs-7671-2018


    I hope that helps!
  • 0
    Hi Alice,


    I've just been onto VitalSource and the amendment is not listed. Our package includes the regs, guidance notes, codes of practice, etc. The Corrigendum from December 2018 is listed but no Amendment 1.


    Regards,


    Peter
  • 0
    Hi Peter,


    I've sent you a separate message.


    Thanks


    Alice
  • 0

    For years, the chassis of every car has been connected to the battery negative.  Changing that would require a re-design of the whole car's wiring system, and probably a lot more copper as every electrical accessory would now need a negative wire.




    I think you underestimate the change in the wiring that making a petrol vehicle into an electric one entails as a matter of course.

    An electric car is not just a 'normal' 12V negative earth system from a petrol car, but with a bit bigger battery and rather larger starter motor than normal and all the internal combustion bits deleted.  Yes there is a small 12V supply derived from the batteries for ancillaries, but that is not the main traction supply, which to keep the current sensible runs at something more like 400V DC, and even so, the currents are such that it does not use a chassis return from the motors .

    The problem is the mains to traction battery charger circuit, which is class I, which makes the EMC problems easier, and almost everything else much harder.



     


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