For those interested in finding out about 3 phase wiring, here is some info on the RenoKu.com website.

* Deciding on 3 phase or single phase wiring

* Photos of 3 Phase Wiring

In my opinion, it's troublesome to upgrade to 3 phase wiring later. This is because one needs to carry out internal rewiring for the house.

I think the most accurate way to determine if 3 phase wiring is needed is to count the max load at any one time of all the electrical appliances in the house. If say, 4 air-cons are turned on at the same time, then calculate the combined load. Not sure of the way to calculate this but your electrician will be able to give you a better answer.