Hi Peter,
Haven't heard from you in a while!
We also use phase barriers in some cases where two or more phases are present in the same box.
It is interesting that North America considers that nothing should exceed 120V to ground/240V between lines in residential whereas in Europe it's considered quite acceptable to bring 220/380 3-phase into a single appliance.
The U.K. position is somewhat in between, but believe me I sometimes flinch at the wiring I see here which is at 240V to ground.
