Hi all,

I am moving into a new house soon, but i heard from some of my friends if i want to put in multiple air-cons or plug points in the house i need to change the power circuit box. How true is this and is the power circuit box going to cost more than 1k ?


Thanks in advance

change more like add

if existing db not big enough can add another small one or change the whole thing to a bigger one

before u decide to add/ change the power box, better a reliable electrician to verify for u whether the power box is of old type or new type, and if it's capable of supporting the total electrical power usage.

some electrical devices like air-cond, microwave, water-heater would eat up quite a lot of power and if not managed carefully would cause undesirable consequences including electrical shocks, short-circuit, power-plug burned, etc etc.

my electrician changed my existing one to 26-way and charged me RM500, is that reasonable?

Is there a general rule with regards to the no. of AC that can be safely connected to a MCB?
Say can we connect 2 nos. AC (1HP) to one MCB (20A)?

existing one how big ?

ahh don't over the power limit ?

20a = p=vi = 4400 watts.. now days 1hp ac less than 1kwatt

but also need to see how your wiring is...

General rule, 1 MCB 1 item.

1 mcb is not that exp after all

I think TS referring db box. It does not provide power, it provide space to store mcb, timer, and fuses

It's not the cost. It's more of the space available to slot in additional MCB

Create the space. Follow the electrical rule.

what does that mean?

In electrical there is a rule to follow. We cannot any how just cincai, cheating or create our ownself of way to do. You can have many way to do it. But always play by the rule.

I know some will said, see no problem many yrs still running. But once problem you already gone. The rule create by the expertise will include the problem side when arise.

Noted... are you in the electrical engineering?

existing one is metal box with one row 16 or 18 slots, now plastic box with 2 rows of 13 slots = 26 slots..

normally how much is the market price for changing db box and add more mcb?

1 of my work.

High power appliances need one item to one MCB, things like aircond, water heater, kettle, fridge, because especially aircond and fridge go on and off automatically because when it kick start it draw a lot of current. When you have share circuit (2 or more items to one MCB), when the powerful item on it draw so much current that the other item will lack of power for that split second. If you connect a bulb sharing with aircond you will see the light dimmed for a moment. When it goes off the access current will hit the other item. what it means your other item will break sooner than its normal life span.

On off on off is no good to share.

Aslo doesn't mean you can just change a MCB with 10A or 16A to a higher Amperage like 20A and then add an aircond to its circuit by pulling the wire parallelly from a nearby point point. This is because a 10a or 16a circuit wire that was in existance is meant for low current. By adding an aircond to the circuit you overload not the new MCB but the thin wire.

One standard is wires come from top to bottom. So when you see your socket, anything above the socket is cable run. Don't drills

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Added on May 25, 2012, 5:00 pmOf course there are looping you need to identify where the main/master source. Last time the electrician told me, nearest to the db box is master.

This post has been edited by weikee: May 25 2012, 05:00 PM

wow so many sifu thanks ... now slowly digesting the info..

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Added on May 26, 2012, 1:54 amhow much is the market price for changing
db box and add more mcb?

This post has been edited by wizard83: May 26 2012, 01:54 AM

i can't recall, mine is part of the project. You should ask few contractor to quote than you will know what the market price.

Few hundred only i doubt you get contractor to come work.

Sigh... Too cheap the contractor not interested, To expensive the customer not interested..

Just want to clarify, is ELCB same as MCB? and MCCB bigger type of MCB?

if im not mistaken

ELCB = earth leakage cb
MCD = miniature CB
MCCB ? never heard before

ELCB = earth leakage circuit breaker.
Detects leakage to earth.

Newer technology which does the equivalent job of ELCB is RCD = Residue Current Device
Detects residue current between L & N.

MCB = Miniature Circuit Breaker
Protects circuit from over current. Handles lower fault current.

MCCB = Molded Case Circuit Breaker
Same as MCB but can handles higher fault current due to it arc containment design and material.

guys,

what is the max number of Aircond we can have in single phase

i recall that one aircon installer mentioned 4-5units 1HP AC. I actually don't know how accurate is that... Maybe someone else can elaborate & confirm this...

That means we can only find MCB in the DB in common house (i.e new 2-storey terrace from developer). will there be any ELCB installed as well?

I reckon ELCB and MCBs are standard components in the DB

1hp = 750w x 5/pcs = 3750/240v = 15.6A. 1phase = 60A

Need to add in startup, and wastage/losses. Factor in 20% will be good, if no water heater can put 10 units too.

Factor till 100% also you have more than enough.