Yes, by the 'box', I meant the fuse box. The other thing that will be changed is the meter (the one outside the house), which will be done by TNB. Only after the meter has been changed will you get 3-phase power.

Can't see your image properly, but I think the 3-phase power itself comes from the new meter that TNB will provide.

If I recall properly, the new meter will be connected to an additional cable from the main 33kv power line. I'm not an electrician, but I think my old 1-phase meter had 3 cables connected, and a 3-phase has 4 cables.

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Added on May 17, 2007, 11:15 amOk, I see your image now.

My power supply is definitely the Low Voltage option II.

I was told that option III is for big bungalows with >5k sq feet of space, 10 air-conds, 2 kitchens, 6 heaters (not the instant shower kind) and above.

Maybe if you were running a Pentagon mainframe in your house you might need that kind of power! LOL

You'll have to pay for a new and bigger fuse box, that's for sure.

I mean, the reason why you'll need 3-phase is so that you can simultaneously use more electrical devices. That means that you'll probably want more power outlets inside/outside the house, which will cost you more money (paid to the wiring fella).

If you only need to use say 2 air-conds at a time, the best bet will be to upgrade your fuse box, which will be a few hundred RMs instead of going 3-phase.

TNB doesn't do any wiring in the house, so you have to deal with a wireman for that. I think charges depend on your exact requirements.

DB box cost 1k already.
The rest is like deposit to TNB, wiring, and workmanship.

That's the circuit breaker lah, my house has atleast 60 in panel. You'll have to check your meter and the wires going in and the distribution mechanism 

3 phase systems should have 3 wires going into the meter, one for each phase, coloured red, blue and yellow.