Hire a licensed electrician. A basic point to keep in mind is that you need 100A PER UNIT-- not 100A going to the house then getting split up to power an apartment, too. This is based on the idea that modern places use a lot of juice -- microwaves, TV/Stereo. dryers, etc -- and this is the minimum amount of power needed for normal household. To make it simpler, it's like having $100.00 to lend out, lend a twenty to somebody and nobody else can use it until it comes back -- the same applies to electricity, if an applince is using that twenty amps then nothing else can use it. Hire a licensed electrician.