> 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.
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.
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.
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.