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EV CHARGING EQUIPMENT

John Peckham
I am hearing from my network of contractors, that have actually read the new 722, that they have been asking charging equipment manufactures for documentary proof to comply with Note 5 of 722.411.4.


They are getting knocked back for asking or in one case a Declaration that says the particular device complies with BS 7671. I think that is wrong to declare that as BS 7671 is an installation safety standard and not a product standard. I believe that as a minimum the equipment must comply with the Low Voltage Directive and be CE marked. I also believe that manufacturers have to issue a Declaration of Conformity. 


BS 7671 722 has numerous references to the various standards required such as BS EN 61851 that the equipment must comply with. I am thinking it may be illegal to offer the sale of equipment that does not comply with the Low Voltage Directive and is not CE marked?


I am hoping the countries top man of equipment safety standards, Paul Skyrme , sees this post and will come on and give us his expert view?


Has any forum member asked for a Declaration of Conformity from EV charging equipment manufacturers and received one?
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    RichardCS2:

    So, at a friend's house there is a 6 mm^2 bond to an up-and-over garage door, fitted so far as I can tell when the house was built in 1990. I would expect all the houses on this estate to have them though I haven't checked. Now would anyone like to argue that the risk associated with this large metallic surface with a conductive handle, touched regularly whilst standing on the driveway and connected to a PME-labelled earth terminal is significantly different to the car plugged in on the driveway?


    Yes it could be argued that this connection could be removed, though on a wet and windy day perhaps the door measures just a few kiloohms to true earth and it is simultaneously touchable with a bonded metallic gas pipe. It may even make contact with the pipe some of the time, at the moment there's a ~1 mm gap but that could easily disappear.


    I am unconvinced that there is a new risk associated with TNC-S and electric cars, rather that the risk is comparable to the others that have existed since the start of the PME era and have either been ignored, not been recognised at all, or deemed acceptably low.

     




    I don't disagree with this, although let's take into account a couple of things:

     


    1. This particular garage door would have been bonded under 15th Ed - only a couple of years later, under 16th Ed, we'd moved away from doing that sort of thing as we saw it wasn't a good idea.

       

    • The PME risk is perhaps becoming worse, as the fortuitous earthing provided by metal gas and water pipes in the street is reducing in effectiveness, as the metal pipes are being replaced by plastic (gas because of corrosion of the metal mains leading to explosion risk, water because corrosion was causing a public health risk, and also leak management).


    So, "back in the day" it might have been the right thing to do, to bond that garage door, but today (and for well over 25 years) it's perhaps not been thought of in the same way.
  • Former Community Member
    0 Former Community Member

    gkenyon:


    So, "back in the day" it might have been the right thing to do, to bond that garage door, but today (and for well over 25 years) it's perhaps not been thought of in the same way.


    But nor is it prohibited (perhaps it should be). If that door frame were 1 mm to the right and in contact with the gas pipe no-one would even consider it. They're unlikely to worry if I bolt a class I door opener to it or use part of the frame as a convenient mounting point for a light fitting. And if I measured it on a wet day when the brickwork was damp I might be forced to consider it extraneous and required to bond it under today's rules.


    Bits of touchable metal that are inside one end and outside the other are hardly rare. At some point we have to decide to either live with the associated risk or conclude that the whole PME thing is a fundamentally bad idea for anything other than flats.

  • 0
    I sort of don't disagree with that sentiment.


    I guess generally, we're getting on and living with things at present ... although it's worth considering that you can't "just TT" many properties if you want to change your mind about "getting on with it".


    With respect to electric vehicles being that the ESQCR prohibits connection of PME to a caravan or boat ... and everyone asks what's different about an EV (or mobile and transportable unit) relative to a caravan?
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    There may well be many other instances of potentially dangerous outdoor metalwork (we have galvanised conduit which serves our outbuildings - incidentally, the supply was TN-S when it was installed) but that doesn't mean that we can ignore new ones.
  • Former Community Member
    0 Former Community Member

    Chris Pearson:

    There may well be many other instances of potentially dangerous outdoor metalwork (we have galvanised conduit which serves our outbuildings - incidentally, the supply was TN-S when it was installed) but that doesn't mean that we can ignore new ones.




    But if we genuinely believe new ones are a significant risk, can we justify the continued existence of the old ones? Should we not at least recognise those cases as undesirable and worth fixing when other work is happening? Or if in reality there are more old ones than there are ever likely to be EVs and we currently have an insignificant number of incidents associated with outside taps and conduits then perhaps it is telling us that we should be ignoring the new ones, that our finite resources would save more lives if used differently.


    More generally, the collision of risk approaches between the automotive and electrical worlds is interesting. If a lost neutral caused the car to explode into a cloud of shrapnel and flame, it still wouldn't make more than a few percent difference to the body count associated with letting minimally skilled persons manoeuvre big steel boxes at speed in a public place. If a car manufacturer had a fixed budget for safety improvement I would certainly rather they spent it on better brakes or airbags than on making chargers class II.

  • 0

    RichardCS2:


     

    More generally, the collision of risk approaches between the automotive and electrical worlds is interesting.


     




    Spookily, the risk of collision causing a death associated with driving an electric vehicle is probably greater than the risk of receiving an electric shock of any magnitude from an EV !

  • 0

    This is all explained in Annexes H and I of the 4th Edition of the EV CoP. Very briefly



    I think I understand the thinking, but isn't this going way beyond BS 7671's requirements?


    If my existing installation happened to be TT - than according to BS 7671 itself, can't I just connect up a charge point without any further consideration as far as earthing is concerned? Likewise if I had reliable TN-S (private transformer say) - even though the system's Earth reference could be tens or hundreds of metres from the EV parking space (which may or may not be influenced by some buried metalwork).


    If PME voltages from buried services could be hazardous, shouldn't we have seen some incidents from other situations where a touch potential from several metres away could be simultaneously accessible - such as metal gates hung on metal posts or the tubular steel handrails often seen linking street to front door outside 'pensioner's bungalows'?


        - Andy.
  • 0
    For reasons which I completely fail to understand, some risks are treated in entirely different ways to others. In some areas a decision is made by "someone" (an entirely hidden person or body) that a risk must be avoided at all costs, often totally unreasonably large costs compared to the risk, say for arguments sake £1 billion per death, and in other cases that deaths on a small scale are acceptable. Here we are probably discussing the first case, whilst all other uses of the car follow the second case. If we changed to all electric cars it is likely there would be 30 million charging points around the country, some in services, most in peoples homes. Let us say that each costs on average £500. Thus we spend 15 billion pounds to save maybe 1 life a year. But we loose 1500 lives in cars from accidents for which we accept as a reasonable risk. There is something completely out of kilter here, and it is this worry about vehicle charging points and the possible risks, which are actually very small indeed. Perhaps someone, preferably the "someone" above, would care to make a reasonable logical case for this difference to me, and the public at large?
  • Former Community Member
    0 Former Community Member
    Dave, it's not the cost of a charging point you need to use in your calculation, but the overall increase in cost from whatever extra safety measures are being proposed against the number of lives those safety measures save. e.g. cost-benefit analysis on type B RCDs, lost neutral detection devices and install costs. I agree that for all but the most basic safety measures we're likely to conclude we should have spent that money on road safety or vaccines, etc. but £500 is clearly not the right number here.


    The harder calculation is then the one of human nature. If you push the cost of a charging point install up to what extent will people decide they can't be bothered and daisy chain 3 extension leads out the window to a granny lead, complete with upturned buckets over all the sockets as we so often see on Christmas lights. Not that we see any significant increase in electrical deaths associated with Christmas lights so maybe that's not as dangerous as it sounds either.
  • 0
    Do an internet search for “Ford Pinto petrol tank” it is estimated that over 500 people were killed and many more maimed because Ford wanted to save a dollar.

    https://www.autonews.com/article/20030616/SUB/306160770/lee-iacocca-s-pinto-a-fiery-failure

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