thats because the neutral is for single phase only.. 3 phase doesnt need the neurtral to operate...

In practice, we don't use 240v, is safer to use 230v because TNB do not guarantee supply to be at 240v constant. I know the industry use to have fluctuate and can be -6% to +10%, residential should be very far off.

For say a row of houses using single phase and is distributed between the R, Y, and B, all using single phase still tap into the same Neutral.

correct... the neutral cable already been calculated for... so your point is...
what about the earthing? the earthing is always the smallest cable among all..?

I don't think I have to 32A DB because the upper flr does not have the 32A circuit breaker.
and I notice there are 2 diff color for the MCB?

..

This post has been edited by mikicun: Jul 12 2013, 10:50 PM

the 32A fuse is for both DBs.. ground and upper floor..

2 diff color of mcb; 1 for lightings and 1 for sockets

Just to make sure we are at same page not many people know why only one neutral and the thickness are not 3x of live wires.

Earthing is usually no load and will trip even with small load. If earthing to carry load is acting like neutral. If you want to try can bypass the ELCB, try Live + Earth equipment still power up. Neutral and earth/ground are identical both go back to the earth, house just that house ground are nearer compare to neutral ground. Not sure if you understand what i mean.

I see how some people do creative wiring to reduce the bill by playing around with earthing Still the house have neutral and ground. Really respect.

Than you need to check

01) Your master fused (beside the meter) is it 63amps or smaller. If smaller you also need to check the wires after the fused can it support up to 63 amps.

02) From the Master fused to the house MCB/circuit breaker you need to check if the wires are thick enough to support 63amps.

If all can support 63amps than you can just change to bigger fused and bigger.

Best ask your electrician to check If you don't understand what i mean.

He should survey what kind of power is coming in before shoving 2x 32 amp boxes in there. A little bit of homework saves a lot of issues in the long run. On many industrial 3 phase applications I've done, we sometimes keep the neutral skinny if we are connecting to a well balanced load to save costs as allowable by AS3000 or other relevant standards.

You don't need the same size of neutral conductor for a 3 phase because Wye 3 phase systems are inherently balanced. Thus if you correctly balance a 3 phase system you'll never need more than the sum of 1 output conductor (actually you won't even need a neutral).

That's why TS should get a proper electrician to survey everything. A good electrician will figure the best way to balance everything. You'll never get perfect balance, but getting close is best. Also an electrician can see if anyone has daisy chained the circuit which is very common in houses, whereby instead of wiring in new cables, people just daisy it off the nearest circuit. If you're daisying off an already heavily loaded circuit, add something like a fridge will create problems.

My early post was assuming he have 2x 32amps, picture was not clear and seeing from a smart phone is not easy. If its only 32amp, TS need to properly check the incoming cables until the DB.

3 Phases equipments will have (should have) well balance. Problem will be house uses 3 phases incoming.

I never like daisy chain (usually in china-man term is looping), still prefer direct.

TQ everyone for your reply,

I apologise for the small and low resolution pictures.
I called my developer telling him that I want to change to 63A.
He said will discuss with the electrician and informed me about it.
My house is double storey terrace, 20x70 feet.
actual space of the house i think about 20x40 feet.
Developer spec of the electrical supply.
Light point-18 nos
Power point - 9 nos
Fan Point - 7 nos

I know they are not enough so I plan to reno my house after my house get CF.
Any sifu can give suggestion how many points should I add and roughly the cost?

Many thanks.

Hi sorry i am noob for electricity,

just want to ask, if let say a 100A with 3 phase DB, inside the MCB will need to use 100A each or just add on 20A+20A+20A+20A+20A =100A?

Just add 6A, 15A & 20A mcbs... For protecting the lighting, aircon and sockets ..

An ordinary 3 bedroom house would usually use a 40Amp DB and the 100Amp DB is usually an industrial or commercial lot..

3 phase supply of 100A can support 300A load (over 100A x3) provided all loads are balanced.

The 100A is main supply to ALL circuits in that DB.

For individual single phase circuits follow the 6A lights, 20A sockets with the proper copper sizing.

If you run 3 phase equipment then please call a proper wireman (PW3/4 certified) as this is commercial or industrial use, you don't want someone unqualified to "anyhow install"