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EV Charging Advice

Discussion in 'Electrics UK' started by jeds, 8 Jul 2021.

  1. jeds

    jeds

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    I am in the middle of building a porch on the front of the house and now would be a good time to put in a cable for a future EV charging point. I may or may not get it connected myself but reckon it might be a good selling point later.

    I am looking at three core 6mm² Doncaster EV-Ultra power+data. The length will be about 8-9m. The house has a 100amp supply.

    Is that the correct size? Is there something else I should be considering?

    Thanks
     
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  3. AndyPRK

    AndyPRK

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    sounds perfect.

    SWA I assume
     
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  4. davelx

    davelx

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    (edit) Some charger installers would use 10mm² cable for a 7.5kW charger even though not required for the 32A OPD.
     
    Last edited: 8 Jul 2021
  5. AndyPRK

    AndyPRK

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    No they use 6 mm

    only 7kw chargers are available. About 30A.
    6mm is fine.
     
  6. davelx

    davelx

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    Mine didn't, they specified 10mm and I questioned them about it. I know 6mm is fine. But if your installer requires 10mm you may have a problem.
     
  7. ericmark

    ericmark

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    The rules seem to change far too often to be sure what is compliant today will also be compliant tomorrow. Pipes under drives to take cable great, but cable not so easy, what is being done today would not have been done a few years ago.

    Through my life I have both fitted cable and left cable so it can be reused, seldom does it actually get used, one problem is how does an electrician sign to say he has done the work if part already done.
     
  8. jeds

    jeds

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    Thanks for the input. Yes the cable is SWA. 3 cores plus 2 data cables.
    I saw a table from one of the charger manufacturer's which recommended 6mm up to 30m length for a 7kW unit. Would a 7.5kW unit be significantly better?
     
  9. ericmark

    ericmark

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    You seem to have missed the point, EV charging points are in flux, and the requirements are changing all the time, and there are different ways of complying with the regulations, with 6 mA detection and disconnection units for DC and type B RCD's and what is required depends on who has made the EV charging point, so what is required for a Zappi 7 kW is not the same as a Tesla 7 kW, so until you know what is being fitted it is no good putting in the cable.
     
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  11. AndyPRK

    AndyPRK

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    The grid aren’t going to want chargers to go above 7.5 kw though.

    most if not all chargers are variable. So even new chargers should be backward comparable with 7.5kw
     
  12. JohnD

    JohnD

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    These variables.

    Would you be able to set them to 3kW to take advantage of free solar power?
     
  13. ericmark

    ericmark

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    I know chargers at work are 22 kW, seems we have three independent supplies, and when it was looked at with idea of removing the supply, the cost of removal was quite high, so having car charging points means it pays for the standing charge for the supply. Seems was designed to be factory units, now a dumping ground for future projects, so large electric supply not required.

    But watching U-tube video's it seems there are a number of requirements to ensure the charging points do not present a danger, or over load to the system, and each manufacturer seems to have adopted different methods to comply, some which include switch off the earth, which seems odd, but the problem is TN-C-S supplies and how to make them safe for use out doors.

    A few years ago the charging point was considered in the same way as a caravan power point, but to park a caravan one needs I think 2.7 meters gap to the building at closest point, so this caused a problem with car charging points, having a 2.7 meter gap was a fire safety thing, so can't see why a car would be allowed closer, but seems the Zappi method is to ensure disconnection if the supply voltage is not within the 207 to 253 volt window and if there is a DC current over 6 mA, however the Zappi instructions do point out this was not included with early versions, and early versions needed a type B RCD.

    It seems some of the chargers monitor the power used by the home so as not to exceed the DNO fuse rating, but the point is they are not all the same, so until the charge point is selected all one can really do is provide pipes to thread the cable down when one comes to install it. Also issues claiming the grants until one has signed to buy the car.

    I was riding up the street on my e-bike, and I do wonder how most the residents would charge an electric car, cars are parked where really they restrict access, since there is a parallel road it does not cause too much of a problem, but clearly planning permission could not be granted for charge points, there is no disabled access as it stands, but no one in street uses a wheel chair, so no one worries, but the hills mean mobility scooters can't use the parallel road as too steep, I know as I have tried it.

    So it seems likely there will be more rules, most the houses had garages to start with, but the drive was so steep the slightest bit of snow and could not get car out or in, so most converted into rooms, so question will be asked who granted permission? Both my drives rear and front are not usable in snow, but at least I can park car 10 meters or more from my house using rear drive, but front drive around 4 to 5 foot only, but at least I have a drive or two.

    But this means there will be likely more rules and regulations in the future, so to try and guess what they will be is rather pointless, Richard Hamond's crash and the car burning for days has highlighted the problems of electric cars, so there may be rules in the future over where cars can be charged.

    this is the problem, although rare, it may result in new rules as to how close cars can be to a property.
     
  14. AndyPRK

    AndyPRK

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    You should look at a Zappi if you have solar.

    You put a current clamp around the solar (and your supply as usual) and there is an option to only charge the car when the solar can supply it. So its free miles!
    Also the display on the charger front tells you where the power is coming from
     
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  15. flameport

    flameport

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    Those options do not exist, domestic single phase chargers are 32 amps, which is 7.36kW at 230V.
    The three phase versions are 22kW, which is just 3x the single phase versions.

    The actual charger is in the vehicle, the wall connector is just a device which switches 230V AC on when certain criteria are met, mainly that the correct cable and vehicle are detected.
     
  16. davelx

    davelx

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    Yes, I've looked inside mine (it didn't work so had to fix it with the makers support line on the phone - 1 wire had popped out of the MCU and another was in the wrong terminal)- a Type A RCD, a contactor, a microcontroller (MCU), a relay and a couple of switches and indicators and a hall effect sensor for the 6mA DC monitoring. The profit margin must be good.
     
  17. jeds

    jeds

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    Thanks again, I was originally thinking of running the new SWA cable to the consumer unit, but to do that it has to run past the meter box and is a lot trickier to get to. Plus it presents the problem of leaving the cable coiled there. As you know it's not flexible stuff so would be tricky to get it coiled into a box or something?

    I'm now thinking of taking it to the meter box but I need to be sure there won't be connection problems later. Would something like the attached photo be acceptable? Is it acceptable to fit connectors or RCDs in the box itself or is this a no-no? The whole lot will be in a cupboard so either is doable.
     

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