Just wanna ask for a few more opinion here, aircon technician ( they are the ones who installed 3 new aircon for me ) is on the way today. So anyway, after installing the aircon, i have 3 rooms which have all replaced with new aircon, after work done, technician turn on the power switch of the middle room, and current trips, then he adjusted some wiring stuff and on again, no problem. So I thought that was the end of it.

But, 1 day later, I turned on my room's power switch, it trips for the 1st time, technician left, so I did some testing on my own, found out that the trip isn't 100% but happens maybe on the 2nd or 3rd time, sometimes the 1st. My dad says it might be current unstable and due to their own installation wiring problem, I told the technician what I did and he told me to take a picture of my main current's switch, he said might need to change that ( RM 220 ) and test for a few days and see if problem persists, I told him come and check the aircon wiring first because might be something wrong with the wiring and not my house's current not enough. Would like some advice here too, thanks !

TLDR - On 3 aircon's power switch at the same time, no trip, sometimes on 2, trip, sometimes on 1, trip, not fix.

A 20A MCB (mini circuit breaker) serves 2 3 pin sockets is guidelines by TNB. If the technician add another 13A sockets tapping wires from existing one, then can cause tripping.

So is there a way to verify it myself or must rely on the technician's honesty ? Note that the whole process of installing all 3 aircon, technician used back the same old wiring from my existing old aircon, he say wiring no need to change, only need to change the piping etc, and he did, that one i saw with my own eyes.

This post has been edited by Sotsotzaii: Mar 25 2021, 10:16 AM

You can switch off the MCB and see which sockets have no power. It should be only two. Normally they are close together.

Depends on wiring. Some houses has ring wiring. The MCB is 32A and it will serves 6x13A sockets. IF the wiring is not in ring topology, then the 32A MCB serves 4x13A sockets.

Summary of TNB recommendation

1) 6A -- Lights/Fan (If not mistaken 6 points)
2) 20A -- 1x Water Heater point
3) 20A -- 1x Air-Cond using double-pole switch (yes, 1 air-cond 1 MCB
4) 16A -- 1x 13A socket
5) 20A -- 2x 13A sockets
6) 32A -- 4x 13A sockets
7) 32A -- 6x 13A sockets (if ring wiring i.e. wires form a circle to MCb and the sockets are tapped from the ring)

This post has been edited by Zot: Mar 25 2021, 10:26 AM

I'm sorry I'm totally confused. How can I switch off MCB ? Where can I find that ?

If you are not familiar, then get those who know to explain your house wiring. We are dealing with 24V here

Ohh that, ok, i'll wait till the technician comes and see wat he says. He also mentioned that might need to change the main circuit breaker, which costs 220. So based on your assumption, you don't think it's related to aircon wiring and / or using the existing old wiring that connects to new aircon ?

Those non-certified technician can do dumb thing. The wire inside the wall can carry certain max current load. When the MCB tripped, some will increase the rating of the MCB. That may solve the tripping problem since the MCB can now carry more current, but what about the wire inside wall? If those wire are carrying more current than they should be, they can get hot, melting the wire insulator and cause fire. This is one of the factor of house fire due to wiring.

Just to update u, the technician came and they assured me the aircon wiring is no problem, they are technician from a electrical shop, that electrical shop is verified and certified under Daikin's official website, they say even using the old wiring is fine, they say if only one aircon switch trip when we on, then it could be wiring problem, but if all 3 trips at random times when turned on the switch ( not aircon ), then it could be the main circuit breaker, after explaining he changed the main circuit breaker to a new one, and allow us to test for few days before making payment, i'm trying it now by turning on off the switch of all 3 rooms, so far no trip, so could this mean that the main circuit breaker is the culprit ?

This post has been edited by Sotsotzaii: Mar 25 2021, 11:17 AM

The MCB can be faulty. It is not tripping at its rated power. This can be true also. Just make sure the MCB is replaced by same rating.

Would it help u to verify for me if i take both pictures of old and new MCB ?

Change main CB not recommended as you didnt upgrade the cable size..it is not the root cause. Improper match only ALLOWS overload condition to persist and its a fire risk.

Take a pic of existing DB box at your place first.
Also add a close up of the two biggest modules and another close up of the smaller one (MCB) where the AC is connected to.

This post has been edited by ceo684: Mar 25 2021, 12:12 PM

Right now after changing to the new one, tested out so far no trip at all

Below pictures for your reference

OLD MCB


NEW MCB


The A/C Switch that caused the tripping when on, all 3 rooms different switch design, i doubt that's relevant tho so only took one.


This post has been edited by Sotsotzaii: Mar 25 2021, 12:34 PM

In the DB box should also have many many small MCB looking like this:

If the AC connected to C20 type then it should be OK. If connected on C6/C10 MCB those circuit not suitable for aircon.

From the wood base DB it is also about time for a complete overhaul of the DB box due to old age liao.

This post has been edited by ceo684: Mar 25 2021, 12:50 PM

Is this the one ?

The guy changed the ELCB from 40A to 63A

This post has been edited by yongtjunkit: Mar 25 2021, 02:17 PM

So did he switch the ELCB to the correct / matching one ? So far no trip though when I turn on my a/c switch.

Look at the main switch, is the Amp(A) matching with the ELCB

I'm assuming it's the whole house trip

Maybe take a picture of it as well,, looks like this



Or this



This post has been edited by yongtjunkit: Mar 25 2021, 02:46 PM

That Main CB if tripped will cause no power to whole house. If only 3 room have no power in 13A sockets, then it was due to that small MCB. The C20 is the 20A MCB, etc.

That 63A is Main CB which supply power to all that small MCBs.