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EV Charging and loss of neutral

lyledunn
I mentioned in another post that I would contact HSE regarding any issues reported to them arising from loss of neutral and EV charging points. They have responded and confirmed that there has been no incident reported to them. However, they were made aware of a small number of situations that were a result of poor or no load management. I should point out that this is HSE in Northern Ireland.
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    Loss of neutral and EV chargers, WOW! this should be interesting. What do the wiring regulations say??

    Regards, UKPNZap
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    UKPN:

    Loss of neutral and EV chargers, WOW! this should be interesting. What do the wiring regulations say??

    Regards, UKPNZap 


    Well it depends what wiring regulations you are referring to. Here in the North of Ireland we are in a perennial state of confusion with half the population wanting to remain in the U.K. and the other half thinking that the future would be better in an all-island republic. For the moment I can have one foot on ground  to which BS7671 applies while the Irish Regs is applicable to the ground on which the other foot stands. Despite your little quip, UKPN, I think that you know full well that there are several expansive ways proffered in BS7671 with respect to EV charging which are designed to address the issue of a lost neutral in a PME installation. The Irish Regs (IS10101: 2020) on the other devote only 3/4 of a line; “In TN systems the final circuit supplying a connecting point shall be a TN-S system”. My understanding is that this regulation is not modified from HD 60364-722

    Edit; maybe if GK reads this he could confirm or otherwise that last sentence.


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    It is not a matter of the wiring regulations. It is a notifiable incident to the HSE, because it is considered very dangerous indeed to then, and should not happen. Your sarcasm is beginning to grate on some of us. Each incident needs to result in a fine which is significant to the DNO, and there were more than 1000 incidents (reported) last year. I suggest £100,000 minimum per incident as an inducement to actually maintain and replace the networks, some of which at 80-100 years old and in a very poor state. Doing nothing is very cheap, danger never is.
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    Indeed for some time now the example list of  ESCQR incidents (that must be reported to the HSE ) has included
    Events where the failure of a PME neutral causes a rise in voltage above statutory limits


    Along with the long standing traditional stuff like
    discovery of reverse polarity on customer’s premises or street furniture where the error is found to be located in connections under the control of a duty holder 
    any event that results in the death of one or more domestic pet(s) or any livestock (as this would indicate the existence of potential current flow sufficient to kill a person)

    etc.

    Failure of a duty holder to file a report is quite a serious matter, liable on summary conviction (i.e. at the level of a magistrates court)  to a fine not exceeding level 5 on the standard scale. Until  2015, level 5 used to mean maximum of  £5000 , and had been for years but was increased to unlimited - the idea being to allow magistrates the freedom to impose larger penalties on wealthy organizations or individuals, without needing to refer the case upward to a crown court as they would have  previously done.

    So, in principle, the fine or failing to report a broken neutral is unlimited, and has been for nearly 5 years. No fine for letting it happen so long as it v is reported promptly though, unless it causes an accident or injury  that is also reportable under RIDDOR.


    The UK HSE should have some numbers sqirreled away.
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    Yes Mike, I am suggesting that a fine is necessary in order to prevent it happening often, figure from the HSE guy I was speaking too the other day was more than 1000 incidents last year. This is simply down to network maintenance being inadequate, a lot being from 1930s (where I live) and a lot more being older.
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    There is always the possibility that there will be an enforcement notice served on the DNOs making them replace older infrastructure the same as with the Gas suppliers having to replace iron pipes.


     Andy B
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    lyledunn:

    The Irish Regs (IS10101: 2020) on the other devote only 3/4 of a line; “In TN systems the final circuit supplying a connecting point shall be a TN-S system”. My understanding is that this regulation is not modified from HD 60364-722

    Edit; maybe if GK reads this he could confirm or otherwise that last sentence.




    Confirmed, although the Clause number is 722.312.2.1, and the requirement is



    In a TN system, the final circuit supplying a connecting point shall be a TN-S system.





    Interestingly, in IEC/HD speak, this does not mean the supply arrangement has to be TN-S; there are many international standards, which have the notion that in a TN-C-S, downstream of the point of separation of the protective conductor is TN-S.


    As an aside, this creates a unique situation in interpreting those standards which are not incorporated in BS 7671 in the UK. For example, does BS EN 60079-14 permit the electrical installation in a hazardous area to be derived from a TN-C-S (PME) system?



    I would also add that, whilst the UK is presently the only country whose national wiring standard is concerned with the risks of broken neutrals in TN-C-S supply distribution arrangements, other countries are beginning to consider them, as we have seen with the recent discussion thread here.



    ... and finally, I understand for the rest of the UK, we are looking at a recorded average of just under 1 broken neutral event reported today, but the YoY rate of increase is perhaps more concerning. I have not seen specific data regarding damage to equipment or installations, injuries, or worse, just "events".


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    Wdavezawadi (David Stone):

    Yes Mike, I am suggesting that a fine is necessary in order to prevent it happening often, figure from the HSE guy I was speaking too the other day was more than 1000 incidents last year. This is simply down to network maintenance being inadequate, a lot being from 1930s (where I live) and a lot more being older.


    Would anything be gained by requiring the replacement of old infrastructure, unless there was also a requirement to return to "proper earthing" rather than PME.

    Replacing an old DNO main with a new one will require at least two new joints per customer, one joint between the new main and a new section of service cable, and a second joint between the existing service cable and the new piece (it is most unlikely that the EXISTING service will have enough slack to be jointed to the new main)

    Each new joint carries some risk of faults, including an open CNE. A new joint may be a greater risk than one that has survived for decades, at least until the initial failures in the new joints are discovered and dealt with. Though remember that each new joint that blows up probably requires at least TWO new joints for repairs.


    I believe that all new DNO mains should be 4 core plus a separate earth.


  • 0
    "UKPN, I think that you know full well that there several expansive ways proffered in BS7671 with respect to EV chargers which are designed to address the issue of a lost neutral in a PME installation".

    Why would I need to look in a guide book for any information on requirements for a PME connection? The Guide book gets its information FROM the PME requirements list.  Furthermore, BS7671 doesn't always get that right, as we saw from the digging up customers drives to bang endless earth rods to "improve the network" The hairbrained idea was quickly pushed under the carpet when experienced engineers pointed out that it would harm the network. 

    The companies strategy on any issue with any requirement where a PME connection is requested is fully laid out. There is no need for potential users of EV charging units to remortgage their homes to purchase the latest copy of a guide book which will need corrigendum/correction/errata in a few months time.


    Regards, UKPN.Zap
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    UKPN:


     The Guide book gets its information FROM the PME requirements list.  


    Regards, UKPN.Zap


    Reference please, with the recommendation from the DNO on how to connect an EV charger.


    Andy B.


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