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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?
  • 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.

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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.
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    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?
  • 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.

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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
    Yes, I could remove it (and wedge a piece of plastic between the door frame and the gas pipe). My point was more that there are hundreds of these in this estate, and vast numbers of similar situations, many as Lyle points out dating from the "bond everything" era and others an inevitable consequence of normal earthing and bonding practices. There is a logical inconsistency here where we seem to worry deeply about EVs, feel a bit uncomfortable about outside taps and outdoor use of class I appliances, and then proceed to ignore all other TNC-S connected outdoor metalwork. Light switches, gas meters and pipes, electric gates and bollards, garage doors connected via door openers or any other means, most of the caravans on domestic driveways, block heaters, fences with light fittings, etc. The risks are clearly comparable in many cases so either there is a real problem that extends wider than electric cars (and therefore needs dealing with), or the risk associated with EVs is a trivial increase on that which already exists and has been long considered acceptable.


    Perhaps the truth lies between the two, possibly lost neutrals occur rather more often than we are really comfortable with and no-one has really considered the extent of the TNC-S connected outdoor metalwork that exists until prompted by just one more item. Perhaps the whole safety case for TNC-S was too reliant on the rapidly disappearing metallic gas and water mains and assumptions about what equipotential zones could reasonably be created, together with last-century's attitude to risk. One thing stands out though, we don't have a general regulation for not connecting a TNC-S earth to large outdoor lumps of touchable metal, only specific ones for specific lumps of metal that are car or boat shaped. The connection to the garage door is not required, but nor is it prohibited.
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    gkenyon:

    The separation distances that "keep cropping up" in the case of separation of TT systems (2.5 m, 3.5 m, 10 m) are actually based on Figure 16 in BS 7430.




    Graham, thank you for your opinion above. So I think that I would be all right 'cos the service cable is modern and the old PILC one is a good 10 m away where it runs in company with the probably metal gas pipe and probably plastic water pipe. The gas main in the street is still metal and runs very close to the lamp post and the JB to my property.


    I know all of this 'cos being a nosey sort of character, I was present when holes were dug.


    But what I don't know is what goes on next door, so yes I can see that TT doesn't work for everybody.

  • 0
    I don’t think that is the point RICHARD is making. Merely that the door when bonded represents a risk that is often cited for EVs.. Back in the eighties and nineties bonding just about anything that was metal was the message that was perceived by the Hoi-Polloi  if not totally advocated by the oligarchs. I remember heated debates about the bonding of metal window frames and window cleaners on metal ladders dying in their thousands. 

    Regardless of what we as individuals may perceive as risk, the law requires that it is assessed and reduced to a level as low as reasonably possible. To that end we use guidance from relevant authorities so there is no escaping the guidance in BS 7671 for electrical installations or Section 722 of that document and the attendant COPin particular, for EV charging.
  • 0

    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?




    Is the garage door really an extraneous conductive part? ? 


    Surely the difference is that the door isn't plugged into the mains. I'd remove the bonding.

  • Former Community Member
    0 Former Community Member
    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.

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