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Comment by kukkamario | Hacker News Reader

400V three phase is wired to all houses at least here in Finland. All 3 phases are wired to the electric box and then that splits phases to normal sockets and for lighting etc. Ovens use three phases and detached houses usually have separate 3-phase plugs outside for running eg. heavy construction tools, like cement mixer and such. Oh right and sauna stove also needs all 3 phases obviously.

Even apartments have that full 3-phases, but just for plugging in the oven and the sauna stove.

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Its everywhere in Europe. I haven't seen nor heard about say a single oven not plugged into 400V. I've lived in 4 different countries in east & west, all the same. Even when traveling around a bit, I see those special plugs in convenient places, where you may expect to plug something powerful for some heavier work.

Anything high power, you go for this plug. I'd imagine car charging would also benefit from this but not personally in that market yet.

This HN thread is the first time I learned about 400 V to homes in Europe. My oven is 220 V. I just checked the manual. All my house is 220 V. I live in Italy.

Plugs are usually Shuko for high power appliances (washing machine) and two smaller pins for low power (phone chargers.)

By the way, Italy traditionally had a three pin in a line high power plug but more and more appliances are coming with Shuko plugs so wall socket are either bi-standard or just Shuko now.

The 400V is between phases. 230V is between a phase and ground. Ie, you get 3 wires (phases) of 230V from the 400V connection.

Btw, Europe standardized at 230/400V in the nineties. In Czechia we switched from 220V to 230V in 1993. Not sure when Italy did, but probably around the same time.

"Standardized". The allowable voltage for power is normally something like 6%. When they switched from the mis-mash of 220 and 240V to 230V, they specified the allowable voltage range was wide enough to encompass both of those, including the allowable voltage range for 240V. So largely it was just "Everything is 230V now, and try to make sure new stuff is actually 230V".

Yes. “Standardising” to 230V +/-10%, allows for 220/230/240V +/-6% (the previous standards used in different countries) to all coexist without actually changing any equipment.

My UPS most of the time reports just under 240v.

The last transformer between houses and the grid is 440v three phase. As I understand it the distribution networks all look pretty much the same, it’s only the last mile that differs. And thus consumer electronics.

If you want to run a machine shop, it’s a pain but not impossible to get 440 three phase wired straight through to your business. But consumer “heavy” motors and induction stoves run on two phase 230V.

There really isn't a huge advantage for 3 phase unless you are doing high-power DC rectification or trying to run a motor.

The US grid is basically 3-phase everywhere, but it's neither needed nor cost-effective to run it into the home.

Now, the 400V part is different. That would require less copper (but with a safety cost).

Currently probably biggest advantage is electric car charging. It is easy and cheap to add high power fast charger when there is already 3 phases available.

400V between phases so 230V per phase. Safety is provided by making plugs not expose contacts while half plugged. US plugs are really unsafe compared to plugs used in most of the Europe.

And safety provided by having much stricter control and requirements on the whole house electrical system.

Also power tools, with 400v plugs you can go to much higher wattages on circular saws, planers etc.

> detached houses usually have separate 3-phase plugs outside for running eg. heavy construction tools, like cement mixer and such.

Is this sort of use common in Finland? It seems like kinda a waste of money and materials to install the infrastructure to allow everyone to run heavy construction equipment off their home's electrical supply.

I can't talk about Finland, but in Central Europe it's pretty common as there is a culture of house building.

In the US, a developer typically buys an entire neighborhood's worth of land and builds a bunch of houses there to sell to individuals.

Over here, the individuals will typically buy their own small plot of land and then have a house built there according to their specifications. You need to be able to run heavy construction equipment to do so.

How esle is the home going to get renovation work and upkeep done?

Since you need three phase 380V for the sauna and the kitchen anyway, and probably for the ground or air heat pump too... it doesn't cost almost anything to run a cable from the electrical box and installing a three phase socket.

This shows a 32A 400V socket costs under 10 euros: https://www.taloon.com/voimapistorasia-pinta-bals-101-3pne-3...

It is more efficient. Going from 4 wires to 5 is not a big deal if you then can have triple power. Or you can use thinner wires thus less material overall.

The split phase is two lives, neutral and ground. 3-phase is 3 lives, neutral and ground.

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