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Domestic 3 pin plug in question

Discussion in 'The UK and Ireland' started by Twinsparks, Jun 28, 2018.

  1. Twinsparks

    Twinsparks Member

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    I take delivery of my new pride and joy tomorrow and just had a thought....

    Until I get a home charger fitted by an electrician, hopefully in the next few weeks, I simply assumed I could plug in to a domestic 3 pin plug in the garage to top up each night (I can charge at work).

    The consumer unit is a few years old and I’m now wondering whether it can take the load ok (I’m not an electrician!). Consumer unit says 80A max load and has some old looking breakers. See pic

    If any of you have any idea what to check or if you could point me in the direction of any uk relevant threads I may not have spotted it would be appreciated.

    Cheers
     

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  2. WannabeOwner

    WannabeOwner Active Member

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    You can, manually, reduce the "power grab" on the dashboard, so if it trips, or plug gets hot, then just "de-tuning it" should be fine.

    Long-ish (decent quality, and "not skinny" :) ) extension lead, which you might otherwise need when staying with friends?, to a "newer / nearer the distribution board" socket might be worthwhile, if you have a problem. (There's a [extension lead] thread which I can find for you if you need it)

    OK, seen the photo now ... so "trips" will be "replace fuse wire" I suppose :)
     
  3. sidmini

    sidmini Member

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    Hi yes just use the tesla UMC which comes with the car to plug in directly into a 3 pin socket. Don't use any type of normal extension cords or reels they won't be able to manage the heat and will be dangerous. You can buy purpose-built adaptors and extension leads from here: Xavelec - Charging cables and adaptors for your Tesla EV UMC

    You can call your local electricity provider and as them to upgrade your main incoming fuse to 100A they normally do this free. Enjoy the new car!
     
  4. WannabeOwner

    WannabeOwner Active Member

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    I'm no sparky, but unless the various circuits combined are using a lot (Ovens, Induction Hobs, Immersion Heater, Electric Power Showers all on at once!) I don't think main fuse size well be relevant as I assume (which is dangerous ...) that the Garage will be on a 13-AMP Ring, so maximum current draw will be 13AMPs and a bit short of 3 kW, so if "everything else" is not significant then 80 AMPs will be enough ...

    When the wall charger is installed that will be higher wattage (not sure but I think its 7~8 kW) then that might necessitate increasing the main fuse (but it will be a Sparky doing that job who will be better able to advise based on your other usage)

    (13 AMP plug is around 5-6 MPH charge speed, wall charger is 21-22 MPH)
     
  5. Twinsparks

    Twinsparks Member

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    Thanks

    Excuse the stupid questions!

    How long is the standard UMC + cable?

    Plugs will be located within 1-2 meters of car so should be no need for extension cable.

    What fuse wire do you think is needed for the Tesla?

    Will I be alright with 15A or should I go out and buy some 32A?
     
  6. sidmini

    sidmini Member

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    UMC should be about 15ft. Sorry can't advise on the fuse, my electric provider upgrade my fuse. As WannabeOwner said dial down the amps in the car when you charge
     
  7. WannabeOwner

    WannabeOwner Active Member

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    "Generous", definitely more than the couple of meters you envisage.

    needs to be the same size as the fuse-holder you put it into, AFAIK. SO best not to increase it, because the fuse is protecting wire from fuse-to-socket, and if you increase the fuse it will happily allow more power into the wire ... which won't be designed to take it.

    Dunno how many miles a day you need, but assuming plugged in for 12 hours that's 60-72 per day, so if you can cope with that, or you are at home more hours / your commute is shorter then de-tuning would give you enough. (Plus maybe plan to plug in all weekend to make-up for weekday loses)
     
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  8. MagicMagicD

    MagicMagicD Member

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    I've been charging my car using the 13amp UMC since I got it in December; it's workable but can require some planning.

    As far as I understand, you can only have a 100 amp fuse fitted to your 'cutout' if it's externally mounted, not if it's indoors. This is handled by your DNO (e.g. Western Power Distribution in my case) who should be contacted by the charger installer to get approval to install the charger prior to any work taking place (due to the sustained demand, but some installers don't do this even though they should).

    Also, if your house isn't that new (30-40+ years old) you may also have to contend with getting your electricity supply 'unlooped' first before you can get a charger installed, which can be complicated and take quite some time in some cases.
     
    • Informative x 1
  9. arg

    arg Supporting Member

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    This is highly regional - UKPN are keen on 100A fuses; other DNOs won't go above 80A single phase under any circumstances. However, this is normally only relevant if you want to charge more than one EV at once, or if your house is unusually large or has a heavy use of electricity (electric heating etc.). It's almost certainly irrelevant to the OP's original question about charging from a 13A socket.

    Note that charging from a 13A socket with the UMC (or any other manufacturer's equivalent) will only in fact draw 10A. This is because typical modern 13A sockets aren't good enough quality to deliver 13A continuously for hours on end. Even at 10A it is marginal and not recommended for daily use over long periods as you will often wear out the socket eventually - the plug gets warm in normal use even with everything as it should be, and any minor wear/dirt in the contacts makes it run even warmer, accelerating the wear until something melts. For occasional/short-term/emergency use it is fine however.

    Rewireable fuses are not wonderful in comparison to more modern breakers or cartridge fuses, but they aren't a problem in themselves for this use. So long as the garage 13A socket is in reasonable physical condition and is protected by a fuse of at least 15A it should work OK. Also of concern in an old installation is whether wiring, junction boxes etc. are in good condition: from the photo, it looks merely old and otherwise quite tidy, but obviously that's only a small part of the installation that can be seen. There doesn't appear to be any RCD protection, so you are at risk if you do something crazy like running over the charge cable with a lawnmower or whatever else you keep in the garage, but that's a general risk in such an installation rather than specifically an EV charging issue.

    As mentioned above, if you are worried about the quality of the wiring you are plugging in to, you can always use the controls in the car to charge slower than the 10A that the UMC allows for a 13A socket. Since heating is a square-law relationship with current, the good news is that a small reduction has quite a good improvement (reduce by charge speed by 10% and get a 19% reduction in heating); the bad news is that 10A is painfully slow in the first place.

    So in summary, temporary charging from a 13A socket while you sort out something better will probably be fine.

    When you do come to install a dedicated chargepoint, things may get more tricky; the installer's preference will probably be to tap a separate supply after the meter and leave your existing installation well alone (with a recommendation to upgrade it in due course). This may be fine if that can be done easily, but if this is a detached garage or otherwise far away from the meter, then running a new cable there may be tricky. Likewise, bonding cables will require to be updated to modern standards even if the EV charging is kept separate - that's normally only a few minutes' work, but can sometimes be more difficult. And as mentioned above, there may be issues of looped services or too-small supply fuse to be resolved. Usually these are solved fairly easily, but in the worst case you could be looking at some substantial work to sort out your existing installation before installing faster EV charging.
     
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  10. WannabeOwner

    WannabeOwner Active Member

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    Good info as ever @arg :)
     
  11. WannabeOwner

    WannabeOwner Active Member

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    I missed that bit originally. Any reason not to do that and, assuming commute is not long, then favour charge-at-work to at home?

    I charge at work, so my rule-of-thumb that's 5/7th of my charging ... but turns out that charge-at-home is very nearly as much as at work. That will be longer weekend trips, but also some work charging on weekdays where I went straight to client. (Supercharger is 12% overall)

    Meantime you could tart up the garage? :)

    [​IMG]
     
  12. Twinsparks

    Twinsparks Member

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    Thanks arg, that’s helpful

    You are quite right in that the installer is keen to bypass the box and wire directly into the meter. Has quoted £200 for this on top of the install, bit of a pain but probably cheaper than getting the whole garage re-wired plus new consumer unit.
     
  13. Subevo

    Subevo Member

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    I'm using the connector tesla supplied its only 10amp max so only draws 2.4kw as others have said you can reduce it to 5 amps in 1 amp increments from the touchscreen which sometimes I do as I have solar panels and try and match the output from my panels so I charge for free.ive only being doing this recently due to the good weather plus I didn't realise the power was adjustable.
    I don't have a wall charger.
     
    • Like x 1
  14. .jg.

    .jg. Member

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    The consumer unit in your photo is a MEMERA 3 from Eaton MEM. It is old and yours has wire fuses (it was possible to get overcurrent breakers to replace the fuses for this consumer unit but these would not make it any safer). That consumer unit does not include an RCD (Residual Current Device), which would protect you if you received a shock from anything connected through it e.g. a lawnmower. For sure, the electrician would either need to fit a standalone unit (which would have a metal case, a breaker and an RCD) or replace the MEMERA 3. If it were me, I would want to replace the MEMERA 3 and re-wire the garage. If you are already paying for a 32A circuit back to the meter, it may as well be a cable with a rating high enough to handle the 32A charging, plus the other circuits in the garage, in a new consumer unit. The electrician should check the supply to the house and advise/organise getting it changed, if necessary.

    For a few months, I used the UMC supplied with the car, to charge from a standard BS1363 13A socket without any problems. As others have said, the UMC limits charging to a maximum of 10A, when using the 13A plug adaptor. This equates to about 6 miles per hour, meaning you could drive an average of 60 miles per day, assuming you could charge for 10 hours overnight. The UMC comes with either 2.5m or 7.5m cables (and this doesn't include the length of charger unit and adaptor cabling), so it can easily reach a socket within 1 - 2m.

    "What fuse wire do you think is needed for the Tesla?
    Will I be alright with 15A or should I go out and buy some 32A?"

    Don't put higher rated fuse wire in the 15A circuits - the wiring may not cope. If something is to burn out, you want it to be the fuse and not the wiring.
     
  15. Twinsparks

    Twinsparks Member

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    Thanks .jg.

    I am getting an electrician out in the next week or so to give an opinion. I do have a new consumer unit knocking around I bought for this purpose, just never got round to getting it hooked up.

    Plugged the car in last night through UMC using plug into 15A fuse and reduced the draw down to 6A. Got 5m ph charge and nothing got hot. Will easily do me me for a few weeks.

    PS loving the car by the way!
     
  16. WannabeOwner

    WannabeOwner Active Member

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    Wahoo! ... no, that's not right "A North American elm which yields useful timber" ... "North American, another word for yahoo" ... OK ...

    Yahoo! ... oh dear "A rude, noisy, or violent person"

    Hooray! ... nope ... "NZ / Australian Goodbye"

    I give up ... I'll got with Billy Bunter's Yarooh!

    :)
     
  17. Twinsparks

    Twinsparks Member

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    :D
     

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