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What size of MIC (kVa) for new build house for EV

  • 21-12-2020 11:35pm
    #1
    Registered Users Posts: 2,171 ✭✭✭ ECO_Mental


    Hi,

    Building a new house out in the country and am I just looking to get my ESB connection. What size of MIC should I get to be some way future proofed for EV charging, I don't have an EV yet but planning to in the next year or two.

    My house will have Air Source HP, MHRV and I will be putting in solar PV, 3KWp min but probably as much as I can.

    Looking as the ESB site 16 kVa I think is the new minimum I think I should get if I am planning to get an EV. But ESB have 20 kVa or 29 kVa options. There isn't a 3 Phase line near me but can I get 20 kVa or 29 kVa on a single phase, but again are these over kill but I want to be future proofed as best as possible.

    I have this cross posted in the Electrical forum but then though the EV charging will be the main consumer of power in the house into the future so I posted here as well. many thanks


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Comments

  • Moderators, Society & Culture Moderators Posts: 31,238 Mod ✭✭✭✭ Gumbo


    ECO_Mental wrote: »
    Hi,

    Building a new house out in the country and am I just looking to get my ESB connection. What size of MIC should I get to be some way future proofed for EV charging, I don't have an EV yet but planning to in the next year or two.

    My house will have Air Source HP, MHRV and I will be putting in solar PV, 3KWp min but probably as much as I can.

    Looking as the ESB site 16 kVa I think is the new minimum I think I should get if I am planning to get an EV. But ESB have 20 kVa or 29 kVa options. There isn't a 3 Phase line near me but can I get 20 kVa or 29 kVa on a single phase, but again are these over kill but I want to be future proofed as best as possible.

    I have this cross posted in the Electrical forum but then though the EV charging will be the main consumer of power in the house into the future so I posted here as well. many thanks

    Standard ESB connection will give you 7kw charging in the future, similar to every other house in Ireland.

    If you can, and costs are not prohibited, then I’d try get 3 phase installed. This would mean you can utilise the 22kw charging speeds of some chargers out there and be full every night during night rate hours.


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,813 CMod ✭✭✭✭ unkel


    How much does it cost extra as a one-off to get 20kVa or 29kVa? And did you enquire about the extra cost of getting 3-phase? Could be extremely expensive, could be relatively cheap. Handy to have for sure for future proofing your house. Charge your car 3 times as fast if the car allows it, most cars don't (but some do, like mine and the car of the above poster, which can charge at 32A / 3 phase - 23kW) but it looks like a lot of cars will be able to charge at 16A / 3 phase going forward - 11kW and you will be able to generate and export far more solar PV, etc.

    16kVa is fine for a household with one EV (or more, but just one charging at any one time) and a heat pump, as long as you don't have electric showers

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 2,678 ✭✭✭ graememk


    20+ depend on the MV network in your area,

    It could be the standard price (ie the 16,kva) or more.

    Esb won't give you a price until you send the form in, they just refer you back to your electrician for requirements.

    I think 16,kva look for 25mm tails, don't know what size you'd need for 20 or 29. If it's bigger, then getting a consumer unit with big enough terminals in it becomes an issue unless you go for an industrial board.


  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


    ECO_Mental wrote: »
    Hi,

    Building a new house out in the country and am I just looking to get my ESB connection. What size of MIC should I get to be some way future proofed for EV charging, I don't have an EV yet but planning to in the next year or two.

    My house will have Air Source HP, MHRV and I will be putting in solar PV, 3KWp min but probably as much as I can.

    Looking as the ESB site 16 kVa I think is the new minimum I think I should get if I am planning to get an EV. But ESB have 20 kVa or 29 kVa options. There isn't a 3 Phase line near me but can I get 20 kVa or 29 kVa on a single phase, but again are these over kill but I want to be future proofed as best as possible.

    I have this cross posted in the Electrical forum but then though the EV charging will be the main consumer of power in the house into the future so I posted here as well. many thanks

    Its a pure cost-benefit decision.

    16kVA will be more than enough to run your HP and charge 2 EVs overnight on night rate unless you are doing insane mileage on both cars everyday.

    Upgrading to single phase 20kVA+ will be of limited benefit and really down to the extra costs as to whether it’s worth it or not for the rare edge cases where you need to charge quicker at home versus just visiting a rapid charger on the road.

    imo, getting 3 phase would be a better benefit as you can export more Solar excess and get a 3ph HP which tend to last longer.

    Again, it’s all down to what ESB are going to charge you for the uprated MIC but 16kVA will work fine.

    Whatever you decide, get the EV cables run now while you are building. That’s the hardest part of installing the charge points.


  • Registered Users Posts: 2,171 ✭✭✭ ECO_Mental


    Just filling in the the online application for the new connection through the ESBN system and going into the Connection Capacity section and they ask you do you have a heat pump and are you planning to have EV charging. If I select EV charging it automatically selects 20kVa or 29 kVa and 3 Phase. No option for 12kVa or 16 kVa.

    If I say I am NOT EV charging then I can select 12 or 16....

    Is this a new policy in ESBN


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  • Registered Users Posts: 352 ✭✭ pauldavis123


    16kva 3 phase is only a grand.

    They use 100a fuses in the 16kva and the 29kva so I'm not sure what the difference really is of you never want to upgrade from 29kva.


  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


    ECO_Mental wrote: »
    Just filling in the the online application for the new connection through the ESBN system and going into the Connection Capacity section and they ask you do you have a heat pump and are you planning to have EV charging. If I select EV charging it automatically selects 20kVa or 29 kVa and 3 Phase. No option for 12kVa or 16 kVa.

    If I say I am NOT EV charging then I can select 12 or 16....

    Is this a new policy in ESBN

    That must be a relatively new thing. It was always just a case of you needed to get 16kVA if you ticked the HP box.

    The charges for each MIC are laid out here (page 3)
    https://www.esbnetworks.ie/docs/default-source/publications/approved-statement-of-charges-2020-2021.pdf?sfvrsn=224533f0_69

    The unknown bit is where they say "+ MV Network Charges". That could be very little or huge money and those MV charges only apply when you go to 20kVA+.

    A 1ph 16kVA connection is €3500. A 20kVA connection is €2400+MV charges so there might not be much in it and then its better to have the 20kVA.... depends on those MV charges though.

    16kva 3 phase is only a grand.

    They use 100a fuses in the 16kva and the 29kva so I'm not sure what the difference really is of you never want to upgrade from 29kva.

    Are you specifically referring to 3ph there?
    I have a 1ph 16kVA connection and it has an 80A fuse. A standard 12kVA connection typically has a 60A fuse and the 100A fuse is for 20kVA+


  • Registered Users Posts: 352 ✭✭ pauldavis123


    KCross wrote: »
    Are you specifically referring to 3ph there?
    I have a 1ph 16kVA connection and it has an 80A fuse. A standard 12kVA connection typically has a 60A fuse and the 100A fuse is for 20kVA+

    Yeah, three-phase has three 100A fuses, 80A in domestic single alright.


  • Registered Users Posts: 1,216 ✭✭✭ Manion


    Apologies for resurrecting this thread, it's actually one of the top linked on google when searching MIC power supply.

    After reading around and looking at my fuse board. It would appear I've a 80a mains fused and a 63amp consumer unit. House is a new build with a HP from 2016.

    A few questions:

    Can I assume that if I have an 80a mains I already have a 16kVA enhanced supply.

    What exactly does that get me? My understanding is that a 16kVA will allow me to use more power at the same time. So for instance charging two EVs or an EV and HP at the same time with plenty left over?



  • Registered Users Posts: 352 ✭✭ pauldavis123


    The kVA in is somewhat meaningless, it's more about the conductor size going into your unit. I have an old 8A supply in the city centre but it's fed by 25mm square conductors with an 80A main fuse.

    That 8A supply pulls 40kW in the winter no problem. I rang ESB Networks after an ECIR about this a while ago and was basically told if the main fuse has not blown there is no problem.

    More kVA means more ability to draw more power. The weak link is the 80A fuse. ESB Networks will replace it once but will complain the second time according to a spark I spoke to.



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  • Registered Users Posts: 352 ✭✭ pauldavis123


    Three-phase is the way to go, €2k to install but they will limit it soon I would say once EV's kick-off.

    Standard three-phase is 3 x 100A connections compared to a single 80A for single phase.



  • Registered Users Posts: 1,216 ✭✭✭ Manion


    Is this something you've actually done? That pricing doesn't seem realistic.



  • Registered Users Posts: 2,678 ✭✭✭ graememk


    I have a 16KVA supply and the fuse in my consumer unit (well its in the meter cabinet) is 80A. My main tails are 25mm2.

    I got my supply upgraded for the farmyard thats connected to the house.



  • Registered Users Posts: 5,782 ✭✭✭ the_amazing_raisin


    I have a 16kVA connection with 6kW heat pump and 2 EVs with 2 chargers

    It isn't an issue for us because the chargers have load balancing built in, or rather one of them does


    The chargers share the same 40A fuse. The Leaf only charges at 16A so the Zappi will monitor the load on that circuit and slow down the charging speed of the ID.4 so as not to overload the circuit

    Similarly the Zappi monitors the house's usage and will slow down if the heat pump is drawing a lot of power


    When we replace the Leaf the next car will probably draw 7kW, so we'll probably replace the EO with another Zappi as they can do better load balancing that way. The EO can also do load balancing but the version we have is too old for that



  • Registered Users Posts: 1,216 ✭✭✭ Manion


    Ok so it's really about supporting more concurrent load as opposed to faster charging, though obviously if you have to limit the current that will slow things down.



  • Registered Users Posts: 352 ✭✭ pauldavis123


    You will need a new distribution board as well



  • Registered Users Posts: 1,216 ✭✭✭ Manion


    OK, I take it you didn't get this done then or you got it done business? Page 8 listed business charge at 2,430.00. Page 5 has the charge at €3,790 including vat + MV Network Charges. I'd assume I would need an electrician as well, and given what I'm paying for a days work installing a charger and writing a cert, it's hard to imagine I'd have change out of 5K.



  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


     

    Can I assume that if I have an 80a mains I already have a 16kVA enhanced supply.

    Yes but you cant assume your "tails" is rated for 80A. You'd need to eyeball that cable. 25mm² is what you need to see there.


    What exactly does that get me? My understanding is that a 16kVA will allow me to use more power at the same time. So for instance charging two EVs or an EV and HP at the same time with plenty left over?

    Standard domestic has 60A so if you have an 80A main fuse and your consumer unit also has an 80A fuse then you have an extra 20A to "play with".

    Two EV's at full charge rate would be 60-64A and then the heat pump would be another 10-20A depending on the rating of the heat pump. So you wouldnt have "plenty left over" but you have enough to just about run all 3 together at full tilt, which is then where you would use load sensing charge points so that they would reduce their rate to keep the overall house load under your 80A fuse rating.

    In practice you wont have two EV's charging all night every night unless you are doing very high mileage on both, so the load sensing is there just as a protection and wont actually affect your ability to have two fully charged cars everyday.



  • Registered Users Posts: 2,678 ✭✭✭ graememk


    Over thinking this a bit, a lot of charge points have load balancing built in. So the it will slow the charge to not over load your connection.



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  • Registered Users Posts: 1,216 ✭✭✭ Manion


    I'm not really able to eye ball the cable thickness and there appears to be no writing on them. The thing is we've an AC system which is 6.5A, Induction Hob, Dryer, Heat pump and now a EV Charger on the way. It's mainly just piece of mind to know how close we are to hitting our MIC.




  • Registered Users Posts: 1,216 ✭✭✭ Manion


    Some folks are happier to live in ignorance I guess than others. The charger I'm getting has an adaptive fuse so I'm not worried about tripping anything, I'd just like to understand better the options and what different things get me so I can have an informed conversation with the installer.



  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


    You might be able to see the meter tails in your attic?

    ESB will tell you for sure tomorrow anyway if you call them and your electrician will be able to tell too.



  • Registered Users Posts: 5,782 ✭✭✭ the_amazing_raisin


    You're right, a lot of it comes down to resource management. The load balancing can slow down the charging, a bit, but it's very rare that we need to charge both cars at the same time anyway

    Even still, if we push up to the 40A limit for the circuit, that's 9.2kW. Over the 9 hours of night rate, that's 82kWh. On average that's probably around 435km of range

    Divided between both cars that's still 200km per car per night. If you regular daily commute for both cars is more than this, then you'll need more power


    Even then, you can charge a couple of hours at the day rate if needed, it's worth balancing the costs against the cost of upgrading your supply

    The heat pump might not have a major impact depending on the power draw. Ours is a 6kW output so pulls around 1.5kW of electricity. I think with the immersion or backup heater it's closer to 3kW for short bursts


    We haven't had any issues of overloading with the Leaf. We'll see how it goes this winter with both cars but I don't forsee any issues



  • Registered Users Posts: 1,216 ✭✭✭ Manion


    OK, so it turns out after contacting ESBN that I've a standard 12kVA supply. The CU Main fuse is 80A rated but based on the supply the fuse at the meter must be only 60A. She sounded a bit vague about whats really involved in doing an upgrade, suggesting I may need new cables running back to the CU, as per above. Anyway, I maybe getting way a head of myself on this, I hardly expect to be driving from 100% to 0% every day.



  • Registered Users Posts: 5,782 ✭✭✭ the_amazing_raisin


    I've found the folks on the ESBN customer help aren't really knowledgeable about the engineering involved and can't help with any technical stuff. They told me I need a new meter when switching to a Day/Night meter, even though I've a newer digital meter which can do all of the readings already

    My house has an 80A fuse in the meter and 63A on the CU as well. Not sure what the logic behind that was, might be standard but could also be that the electrician probably had a box of 63A MCBs in the van

    It does mean I'm limited to 63A, but if the meter tails support it I also have the possibility to increasing this to 80A if needed (or a but less, since I assume I'll want some buffer between the CU fuse and the ESB one)



  • Registered Users Posts: 2,678 ✭✭✭ graememk


    For 16 kva your supposed to have 25mm² cables from the meter to the consumer unit.



  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


    The CU Main fuse is 80A rated but based on the supply the fuse at the meter must be only 60A.

    That sounds a bit dodgy. If correct it means you can pull more than the ESB fuse and hence easily blow it. Either your electrician put in the wrong fuse or that ESB person on the phone hadnt a clue what they were talking about and you actually have an 80A meter fuse.



  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


    My house has an 80A fuse in the meter and 63A on the CU as well. Not sure what the logic behind that was, might be standard but could also be that the electrician probably had a box of 63A MCBs in the van

    Mine was done the same way and I think it is just down to a lazy electrician not having the uprated CU.

    I got mine changed to "unlock" the extra 20A.... after all, thats why I paid extra for the enhanced supply so why have it limited to 60A like that. I regularly go up to 60A so I'm glad I did uprate the CU.



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  • Registered Users Posts: 352 ✭✭ pauldavis123




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