This isn't any different in the US vs. in Europe. Split phase is done at the last mile, just as it ought to be done in Europe for 3 phase power. I highly doubt entire neighborhoods or districts are serviced with a single extremely large 400V 3-phase transformer in Europe.

Standalone houses usually have multiple houses connected to one single transformer. How much depends on density of the houses. For apartment buildings and other dense power needs, there's high voltage directly into the complex, then it's stepped down within the complex to meet the needs.

US distribution transformers are around 50 kVA, in the EU they are more like 300-1000 kVA, so they can power 10-20x more homes per transformer.

Instead of those little pole-mounted transformers that are common in the US, we have one of these buildings with a large transformer for each neighborhood https://dms-cf-08.dimu.org/image/032ykUus1ixX?dimension=1200...

https://electrical-engineering-portal.com/north-american-ver...

Very interesting. Seems like that works much better as the power demand per house in the EU is lower, and the higher voltage gives you a bit more leeway. Frankly, I would be concerned about voltage drop for the far houses... even 400V is going to have some pretty beefy voltage drop under load unless the conductors are enormous.

> I highly doubt entire neighborhoods or districts are serviced with a single extremely large 400V 3-phase transformer in Europe.

They do currently.

I can at talk for the French and Swiss system.

- Entire neighbourhood are served by a single 400V 3-phase transformer. - For critical infrastructure, you do have sometimes two transformers in redundancy on the same local loop in case of failure on one.

There is no need for the pole type of transformer everywhere in the street with double layers of cable like in Japan or in the US.

One note regarding the pole transformers: in many parts of the US they've migrated to underground cabling and larger transformers. My neighborhood has that, and we have about 1 transformer every 4 houses or so. No idea how big the transformer is from a kVA rating, but pretty much every house has 240V/200A service, so they must be pretty large. The transformers themselves are approximately 3' x 3' x 3' and enclosed in a box at the front of certain yards.

> My neighborhood has that, and we have about 1 transformer every 4 houses or so.

You might find that interesting:

https://data.enedis.fr/pages/cartographie-des-reseaux-conten...

This map references all transformers and distribution lines for the french network nationwide for terminal loops. These are open data: Enedis is a the public operator.

"Poste" is the French Jargon for transformer. BT is for low voltage. HT is for anything >1000V.

Like you will see yourself, the density of transformer is of the order of 10x less than in the US/Japanese model.