Hi sifu,

Can I replace a 63A 1P switch fuse with a 63A 2P MCB ?
how does the installation go about? Since existing switch fuse only has 1 incoming & 1 outgoing...

If only 63A 2P MCB is available, is it usable?

thanks for your detailed explanation.
Forgive my sillyness. Sorry if my question sound stupid.
I don't understand one thing.
Existing main switch (some ppl call it switch fuse) only got  2 holes (1 In and 1 Out). If no choice but to use 2P MCB, won't it have extra empty hole then? Coz it has 4 holes ( 2 In , 2 Out ).

Existing is using something like this.
[attachmentid=10622252]

Then my uncle bought this from outside.
[attachmentid=10622254]

Is it correct to connect the IN and OUT as shown above? Leave the other two holes empty right?

It is preferable to ensure that the RCD/MCB/isolator is from same brand. This way it will fit well when you install the busbar.
Also liability issue, if you fit proton engine into a honda MPV and using ECU from toyota, if the car blows up, I don't think insurance/mfg product liability will cover.

Also, for own house, preferably get the whole system from ABB/Hager/Schneider. These are reputable brands with easily 10-18 countries' certification.

The CE logo, to be honest is just suka suka self declaration [CE marking does not provide any specific information to the consumer. It is not a quality assurance declaration, it does not show evidence of third-party testing, and it should not be confused with any independent certification mark of the type issued by international or European notified test bodies.]
Seconded. When talking about main switch replacement you're dealing with live TNB feed of 230V at thousands of amps.
Just 0.05A is all that's needed to kill a person.

If working BEHIND the main switch isolator, that one is much safer since L and N are cut off from TNB safely. But to touch those live wires (since there is no isolator installed currently) it is a very risky thing, call an electrician.

haha, because recently read some articles about switch fuse and MCB, noticed that it is common practice to use 2P MCB as main switch.


thanks for your diagram. Appreciate it.
After watching some youtube videos I gained better illustration on this diagram.
It's true. Thanks for your warm advice.

I really have no idea, sir. I am not good in electricity thing. I just noticed many new DB using 2P MCB as main switch hence asked this question.. If you tell me switch fuse is still a good thing, I will just let it stay there until it blows (don't know when haha).
By the way, would you spare some time to comment on my shop's 3phase DB posted above? Thank you Sir.

Yes sir, I am particularly concerned about the reversely-fed RCCB and MCBs.
The RCCB model is CDL7463YC. Brand "Delixi".

Yesterday night I read one article, which says "if the RCD does not specify LINE and LOAD on the terminals, mean it can be reverse feed. If it does specify, then must follow accordingly". I am not sure this statement true or not.

Yeah, circuit says top feed, but in actual it was bottom fed instead.
Could you see the Outgoing (from switch fuse) actually connect to the bottom of that RCD.

The previous Maxguard RCD did not trip when I pressed "T" . Hence the replacement. Asked an electrician to come and he had only this brand for 63A 4P 100mA RCD.  If 300mA, he has Maxguard. I chose 100mA.

Relieved to hear that.
I press T every month. Just early this month found out it won't trip.
Could you shed some light how to interpret the diagram,  particularly to check whether it can connect top or bottom?

Yesterday i studied many diagrams, only the ABB diagram labels 1/2 at top, 2/1 at bottom. Most other brands label 1 at top, 2 at bottom.

Unfortunately there is no guide/manual inside the box . What a cap ayam...