This is probably more a power company issue than anything else.
It is unlikely that a residence will have three phase power, with one exception:
Some larger apartment buildings have three phase power. Each apartment has there own panel with a three wire feeder, using two of the phases and the neutral. The wiring inside the apartment looks like single phase, but you only have 208V line to line, and you _always_ have to count the neutral as a current carrying conductor.
-Jon
