RCBO/RCD must have two cables on top and on bottom so it can operate. Yours is 1000% dummy and serves no purpose. Refer my pic the top right, far right RCD (the big block).
The RCD on the left not connected, that time didn’t install second WH yet, no moneh

In any case it should be double protection as in one mains 63A 30mA output (Load) to the 10mA input (Line), not line to line connection. The idiot who installed this don’t know what he/she is doing. Pls get a proper wireman certified with PW1/PW3 certification to make it good.


The WH RCBO/RCD supposed to be sub/final circuit not the main circuit (main power outlet). In this case shutting off the main RCD and MCB does not cut power to entire house since WH circuits are still hot. Pls bear in mind this is very dangerous ⚠️

This post has been edited by ceo684: Aug 14 2023, 08:27 PM

RCBO is compromise solution due to lack of space usually.
No harm keeping because 25A is ok for high quality 2.5mm2 cable like Mega Kabel but most of the time substandard cables tarak laser marking or embossing were developer installed so you have an idea how “good” lah, hence having 20A MCB for WH better (Derated for safety) which most RCBO is 25A which is kurang sesuai when used with substandard cable.

Because it is quite a frustrating job to identify the correct neutral if not setup correctly in the first place. They cut corners. Not to say impossible but they really not trained in electrical safety and/or “not my house syndrome”

I’m not in town, but you can contact En.Isa +60 11 5116 5849 if you’re kinda near Shah Alam, he also does good work

This post has been edited by ceo684: Aug 14 2023, 08:11 PM