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

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

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+

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.

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

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

Page 8

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.

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.

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

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)

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.

Do NOT do this!