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Provision for Electric vehicle (plus Induction oven)

Discussion in 'Electrics UK' started by Mr.B, 20 Aug 2021.

  1. Mr.B

    Mr.B

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    I'm toying with the idea of making preparation for an EV on my (private) driveway and, at the same time do a bit of "forward thinking" in case I, or ther next person that lives here, wants to fit an induction hob in place of the current gas one.

    I believe the charge point is something like 7kw and a similar figure for the hob.

    Essentially I'd like to do the cable run myself (it's a bit awkward and time consuming) and have a sparks connect it, plus the fused switches, of course
    .

    My thoughts revolve around coming from the electric meter (which is surface mounted in a cabinet on the front wall of the house) and running up and through the loft and eventually emerging at the attached garage ... no problems with the run there - a 28mm gas pipe follows the same route through the loft.

    I had visions of terminating the cable with a two way (fused?) switch just inside the garage and from there running separate SWA feeds to the hob and/or the EV charge point as and when required.

    My simple(ish) question is whether a 15 metre run of 10mm SWA cable would comfortably accommodate both purposes. A neighbour has had an EV charge point fitted and their contractor installed an isolating, fused switch just under the electic meter cupboard (same as mine would be) having taken tails from the incoming supply ... they then just ran the SWA round the corner to the charge point. My charge point isn't so conveniently placed.

    This is my first enquiry, obviously I'll need to speak to suppliers and/or contractors but the choice of apparatus seems ridiculously variable at this early stage - I'm hoping it'll be clearer when I dig deeper.

    Thanks.
     
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  3. ericmark

    ericmark

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    First EV charging point, there are a few problems to be considered, one is the load, some EV charging points monitor the total load so the vehicle only has power when it would not cause an overload to total supply, so it may need extra wires to monitor this load. The second problem is earthing, with an earth rod (TT) or a separate earth (TN-S) it is not really a problem, but where at some point in the supply neutral and earth are combined (TN-C-S) then special methods are required, this may be an earth rod either to monitor or to convert to TT and with latter distance from TN supply is important, or it may be a safety disconnection system where it the volts are not 207 to 253 volts it assumes loss of PEN and disconnects first the lives (line and neutral) and then the earth. And last with EV charge points and solar panels you can under fault conditions get DC on the supply, this can freeze the RCD used for protection, so either it needs to measure the DC and if it is over 6 mA auto disconnect, in which case a type A RCD can be used, or you need to have a type B RCD which are expensive.

    As a result EV charging points require the electricians to have special training, and also they need to be registered so one can claim the government assistance. It is not a DIY job, even the location is important, charging inside a garage is different to outside, and outside normally looking for a distance from other bonded (earthed) things so there will be a safe voltage gradient under fault conditions. EV charging points can be rather challenging to fit in a safe manor.

    As to hob the induction hob uses less energy to cook food to any other hob, as it puts heat direct into the pan, you can get hobs that use a 7 kW supply, but unless commercial cooking the time it uses this power is very short, some use a 13 amp supply, mine has the ability to supply one heat area with 3.7 kW but in real terms can only be used to boil water, any food would burn, so the standard 1 - 9 setting only uses 1.7 kW approx and very rare to use over 1 kW per heat area. So both oven and hob can be supplied with a 32 amp supply. Unlike the EV charge point which may take full 7 kW for hours on end, the induction hob takes the power for a very short time.
     
  4. Mr.B

    Mr.B

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    Thanks muchly for the information, ericmark.

    Firstly, now you mention it the house opposite which I referred to did have an additional wire tagged alongside the SWA cable. I say "did" because the property is privately rented and the tenant who had it installed has moved on and the current tenant didn't want it and so the charge point, cabling and switchgear was all removed (it was a Pod Point and the unit itself was what I would call huge).

    I can only point out that the sticky label on the supplier's equipment says "Protective Multiple Earth". The house is on a modern estate in Devon and was built in 1996. I'll try to upload a photo and post it separately. I'm not aware of an earthing rod being visible.

    All noted regarding the hob, ta. The Mrs. is attracted by the ease of cleaning an induction hob but does a lot of wok cooking and worries that the glass surface would be scratched badly by the use of a wok being agitated back and forth ... but that's neither here nor there really - it was just me thinking it would be a good idea to provide for one in the future.

    * IF * it was possible to run a supply to both the EV charging point AND an electric hob does my idea of running 10mm SWA and terminating in a two way unit within the garage sound generally feasible? The EV point would, almost certainly, be sited outside the garage ... although I'm interested to learn that there are different regulations regarding whether it was IN the garage or outwith the garage.

    Further thanks. A most enlightening reply for which I'm very grateful.

    Photos below.
     
    Last edited: 21 Aug 2021
  5. Mr.B

    Mr.B

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  6. AndyPRK

    AndyPRK

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    What I don’t get is why you seam to want a hob in a garage lol.

    or why an EV charge point and hob would be in the same location!

    if your cooker circuit is on a 32A Mcb is maybe capable of having an induction hob connected to it.

    As for the charge point. You may want 6mm swa or swa ultra cable
     
  7. Mr.B

    Mr.B

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    I don't want a hob in the garage. I should have made it clearer - if the SWA terminated in the garage on a two way fused switch it would allow me (or a future occupier) to run (a) a short run of SWA to the, adjacent, outside wall on the driveway and (b) a short run of twin and earth or SWA through the internal wall between the garage and the kitchen to supply the hob.

    The cooker is on its own 32 amp circuit but I wasn't sure it was OK to connect the two.

    Not quite sure what you mean regarding the 6mm. Could you expand a bit? ta.
     
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  8. AndyPRK

    AndyPRK

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    You say you want to run 10mm swa.
    You may only need 6mm swa for a charge point.

    however as it could power the garage also, maybe 10mm isn’t a bad idea. unless the garage also has a juicy supply already.

    ultra cable contains cat5 which can be used for the charger to access the internet (if Wi-Fi is poor at the location)
    Or for the charger to monitor the current consumption of the house and reduce charge when necessary
     
  9. EFLImpudence

    EFLImpudence

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    Why bother?

    What if the next person who lives there want two charging points - or a hadron collider?
     
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  11. Mr.B

    Mr.B

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    Reply to Andy PRK .... thanks .... the garage has a power supply already.

    My thoughts regarding 10mm (as opposed to 6mm) related to my proposal to allow for the hob in the kitchen if the Mrs decided she fancied one. I only plucked the 10mm figure from the air really - I just guessed that to run the charge point and the hob would need it. Maybe it doesn't.

    Additionally, you've raised the point of running the induction hob from the existing 32 amp cooker circuit. As mentioned, I wasn't at all sure it would be permitted. I suppose I was thinking if someone, subsequently, fitted an electric hob that wasn't induction (i.e. a conventional electric hob) then that might be exceeding permitted regs and could be hazardous.

    The ultra cable is something I was unaware of. I gather you're suggesting it would do away with the need for a supplementary wire to run alongside the SWA between the meter and the charge point (which ericmark mentioned and which I'd forgotten about).

    I would reiterate that I would have a sparks connect everything ... I only proposed doing the monkey work and was doing this early research so as to have a bit of an idea what specs the cabling would need to be. I'm not a sparks although have done quite a bit of domestic electrical work in years gone by when rules allowed you to do your own work.
     
    Last edited: 21 Aug 2021
  12. flameport

    flameport

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    You already have everything required for an electric hob, double oven, single oven, freestanding cooker, or various combinations of those things.
    You don't need another circuit.

    An EV charge unit requires it own circuit, which would normally be taken from the existing consumer unit just like any other circuit in the house.
    If that consumer unit is old or unsuitable, replacing it with a new one is the usual choice.

    A cheap-o-matic option favoured by those who specialise in slinging in substandard EV points at the lowest possible price is to shoehorn a switchfuse or mini CU into the meter box, which is neither permitted or desirable.
     
  13. AndyPRK

    AndyPRK

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    In summary you don’t need to do anything till you want a charger.
     
  14. Mr.B

    Mr.B

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    All the above received with thanks.

    And so ... if I've understood it right it's OK to come off the existing 32amp cooker circuit which currently supplies a conventional, built in, Siemens, double, fan assisted oven and feed a new induction hob approx. 3 metres away.

    That's straight forward.

    The trouble with running the EV point from the existing consumer unit is the cable run is physically difficult - the Consumer Unit is on one side of the house and the garage on the other ... hence my thoughts about going from the meter position and running up and over - and means quite a lot of disturbance and redecoration and providing coving to cover the cable.

    But flameport is advising that the option to come from a switched fuse adjacent to the meter cabinet (as was done in the neighbour's house) is neither permitted nor desirable. Clearly I didn't know that.

    Further thanks. The advice has shed much light on the situation. I'm obliged.
     
  15. winston1

    winston1

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    Or as in post 3 doesn't want it and rips it out.
     
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  16. ericmark

    ericmark

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    Unfortunately this is all too true, I looked at the screwfix charging point [​IMG]it seemed until I read the spec a good duel purpose unit, could plug in lawn mower or hedge cutter or visitors electric car, but on reading the spec I was rather disappointed to find in real terms in my property was the same as this [​IMG] so £49.99 v £8.23 to do the same job, I don't need RCD or MCB protection supply ear marked for outside socket already RCBO protected, so in my case pointless having a second RCBO next to socket. Farnell publish the data sheet which seems to say the supply to it should be protected by a type B RCD so see no point in ever having a RCBO fitted into it?

    The Pod Point unit does a lot more, it states
    but the unit for direct connection to PME or TN-C-S has to also have a disconnection device which auto disconnects line, neutral and earth should the voltage not be within the 207 to 253 volt window, it seems the 50 volt limit has been raised to 70 volt to allow for charging points using this system, however back in 1975 when the government changed the rules on portable traffic lights I remember a problem with 55 volt and it was stated 25 volt is enough to kill a cow, and all our traffic lights had to go back to be modified.

    Although 50 volt may be safe for a biped, it is not safe for a 4 legged animal, and the larger the animal the greater the distance between legs so the shallower the voltage gradient required. So be it a cow, sheep, dog, cat we have to consider will these be around, clearly in a garage no problem, but cats and squirrels often seen in my garden and would welcome visit by fox or badger, but would not want them to die on my property, not sure how I would get rid of them if they did, badgers are heavy, and would not want dead one in my car.

    So even following the rules that are questions as to safety, personally I think TN-C-S should be outlawed, but can't see that happening very soon. OK in the main problem is copper theft, but we know people do steel copper, and also road works have caused same problem. It is only a matter of time before some one is electrocuted by touching an EV car or charging point with a TN-C-S supply.

    The other point is fire, it has been pointed out there is a lower percentage of electric car fires than petrol, however since most of us now drive diesel that is not really helpful, but the problem is putting the fire out, at the moment it seems dropping whole car into a container of water is best method, not really an option if car goes on fire in a garage. So the big question is it safe to charge an EV in an integral garage?

    upload_2021-8-21_13-33-5.jpeg we are shown pop up EV charging points, do you really think a wheel chair or even push chair can pass that? And at that hight it is asking for some one to walk into it, clearly not an option to turn off street lamps with one of them in the street. Yes my house has a rear drive where a EV can be parked on my property far enough away from house to be safe. However a fire engine would not reach it so would be a problem with fire.

    I can see in the future the rules on charging EV cars tightening up, I walk up the road to post box and see all the houses where the integral garage has been made into a room and the car parked on the road, and until some one complains likely they will stay there, however the county council could hardly give permission for a car charging point on a road where there really is not enough room to park the cars. Yes there are two charging points in the town, they are where I work, and they are getting used more and more, so really even at 22 kW not enough to serve all the visitors. Oh and they are on a TT supply.
     
  17. AndyPRK

    AndyPRK

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    Saying its not desirable is going a little far, however DNO's are getting $hitty with people installing things in meter cabinetts. I thought a corner of the cab could be used for customer equipment.

    Anyway, if you wish to avoid that, there is an alternative of putting a small switched fuse inside the house, close to the meter cab (within 3m of the meter), and then a cable going out again to the garage. Maybe that would work better for you, should to wish to avoid Controversial issues

     
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