Comment on The "standard" car charger is usually overkill—but your electrician might not know that [32:26]

• antimidas@sopuli.xyz ⁨3⁩ ⁨days⁩ ago

  Let’s go for a standard single family home example. Level 2 charger is either 8 A (5.5 kW) or 16 A (11 kW) three phase. On top of that, typical sauna is 6-7.5 kW, 1-2 heat pumps (approx. 1.5 kW a piece), stove (8.5 kW max), water heater (2-3 kW), + other appliances like dishwasher, washing machine etc.

  It would seem like that easily trips the breaker, but you won’t be charging the car and warming up the sauna at the same time, unless opting to 5.5 kW charging. However, you typically charge the car at night, when the other things running are the heat pumps and the water heater – this will end up drawing around 16 kW total (in the worst case scenario) which fits in the limit. When you don’t count the car into the mix, there’s plenty of power to go around.

  There are multiple reasons behind this. One is our homes are relatively well insulated, which means that we can get by with a lot less AC and heating. Appliances in the EU are also generally more efficient – as an example, our dryers are typically based on heat pumps and pull a lot less amperage for the same performance. Lot of homes also don’t have a dryer. Stoves have generally lower power requirements as well, and practically never draw peak power. Here’s an example washer+dryer combo where the suggested fuse for the whole thing is 10 A (meaning 2.3 kW available for the combo).

  So listing the same appliances you have (at 230 V single phase equivalent for simplicity, i.e. 75 A available (3 * 25))

  • level 2 EV charger: 24-48 A depending on chosen speed
  • stove: 20 A
  • Heat pumps (also used for AC) worst case scenario approx. 15 A, practically only reached in extreme cold
  • dryer and washing machine: 10 A
  • water heater: 16 A

  Which will result in 79 A total worst case or 103 A depending on the car charger spec. A bit over the 75 A available, and not calculating additional smaller loads like the microwave, kettle, TV, lighting etc. That worst case will in practice never be reached, though, and even the main breaker typically has some tolerance before it trips (usually main breaker is using a slow-blow fuse equivalent profile, which doesn’t immediately trip with a minor overload or a short spike). Our code mandates enough tolerance in wiring gauges that this doesn’t pose any risk.

  Why don’t we want the added headroom then? Upgrading the service from 3x25A to 3x35A isn’t really that expensive in urban areas, and can be done relatively simply? Well – Finns are stingy and depending on who happens to own your local distribution grid you can get heavily penalized monetarily in the long term, when upgrading the service to a higher tier. Caruna owns a lot of the Finnish distribution grid nowadays, and as an example from their pricing chart going from 3x25A to 3x35A raises your monthly base rate from 29.71 € to 51.68 €. That’s 240 € extra per year, which is a pretty high cost for a just in case that’s easily avoided. In cities that still have municipally owned distribution (Lahti, Turku, Helsinki as an example) the costs are typically much lower, both for upgrading the service and monthly costs, compared to the privately owned grids.

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  • AA5B@lemmy.world ⁨3⁩ ⁨days⁩ ago

    As a European those power draws listed sound absolutely absurd to me

    Let me clarify - those are standard sized circuits, not actual draw. However the service has to be sized to handle it, and over-provisioning to account for it.a customer might install a stove that draws the full load and might use all the burners at once, and you have to account for typical usage patterns.

    For sure it’s a well earned stereotype that Americans use more electricity than many other places. We tend to have bigger houses, more and bigger appliances. We not only don’t have that base charge per size of service but too some extent are charged less to use more: essentially we subsidize people electric resistive heat, who can pay a lower usage rate. We also don’t usually have time of use metering, although some do: my rate is the same whether I charge my car at night or at peak time. And of course our current leadership is intent on rolling back the efficiency standards we have.

    Taking your heat pump dryer example, those are finally available here but tend to cost a lot more than a traditional dryer: savings on efficiency will never make back the extra purchase cost More importantly they’ve only been available in small sizes, not typical for houses, especially with families

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• Zenith@lemm.ee ⁨3⁩ ⁨days⁩ ago

  Aside from the heat pump we have all of these things and they’re often running all at once. Never had an outside

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  • AA5B@lemmy.world ⁨3⁩ ⁨days⁩ ago

    There’s a standard

    • ask-the-electrician.com/residential-electrical-lo…

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    • antimidas@sopuli.xyz ⁨3⁩ ⁨days⁩ ago

      At least here the electrical service base rate is largely set by the max amperage you can draw from the grid. I’ll use my own home’s electricity cost breakdown as an example (all listed prices, even the additional tax, include our 25.5 % VAT)

      1. Monthly base rate for your main breaker, depends on your grid operator – mine is 7.63€ for 3x25 A connection (among the cheapest grids in Finland, I previously used another example often seen in smaller cities, which is 29.71 €/month)
      2. Transfer costs, 0.0187 €/kWh during day, 0.89 €/kWh during night
      3. Electricity tax, 0.0282752 €/kWh, includes national energy security taxes as well
      4. Cost of the actual electricity, typically ranges from -0.05 €/kWh to 0.20 €/kWh with yearly average being about 0.055 €/kWh
      5. Electricity company’s margin for spot prices, 0.004 €/kWh
      6. Electricity company’s base rate, 4.90 €/Month

      For many cities in Finland the base rate for grid connection is considerably higher, and especially for apartments tends to be the majority of your electricity bill outside major urban centers. Even in cities it makes up a large percentage, so there’s a big incentive to not overspec your service.

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      • AA5B@lemmy.world ⁨3⁩ ⁨days⁩ ago

        That may be the entire difference, we don’t have that base cost. Our monthly bill is mainly the actual useage, itemized into generating cost, transfer cost, fees and taxes. There is usually an administrative fee but that’s fixed cost.

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