[lioeters]

> In Europe, three-phase 230/400 V is most commonly used. However, 130/225 V, three-wire, two-phase electric power discontinued systems called B1 are used to run old installations in small groups of houses when only two of the three-phase high-voltage conductors are used.

[ta988]

I know how to wikipedia too! They said usually, not "in some really rare cases"