On Wed, 01 Feb 2017 16:38:12 -0000, "James Wilkinson Sword"
wrote:


Three phase is on the national grid. Supplying only one phase off that would be lop-sided. That's why all three phases come right to every transformer in the UK, then alternate houses are connected to each phase.

If you only fed on street that might be a problem but they alternate
the load by distributing the 3 phases along roughly equal loads on
multiple streets.
It basically just saves them wire. The neutral will be going
everywhere, common from primary and secondary and a single phase
conductor on the primary. We use wye distribution here.
We also end up with more transformers than you see in europe. There is
a transformer for every 1-3 houses. That probably got started when
houses were pretty far apart and it was more efficient to distribute
medium voltage than to try to go very far with low voltage.