~Also, 3-phase appliances are practically unheard of here outside of a commercial environment.
Likewise on my side of the pond. Have only seen one private home (1-family residence) with 3-phase power. (Was owned by an electrician).
The only 3-phase "appliance" is the central air-condtioner. As a matter fo fact, the home has natural gas heating, hot water, cooking and clothes drying.
3-phase power was only available due to the house being in an area zoned industrial/commercial and having such "land-use" nearby. When "220v" here is obtaind from 3-phase source it is called (and is) 110/208v.
I am blisfully unaware of a 3-phase power receptacle for use in a residential setting.