You are welcome.

It doesn't matter... but I would recommend the 1st place just before the switch (outside your bathroom with the on-off switch together) - it would work to track the current movement along the circuits already. I don't recommend putting it in the wet area (inside bathroom especially) so I would not recommend option 2 which many would usually put beside it. It is not an IP65 66 or whatever IP rated device.

Cannot get job if use proper specs. Total bill few hundreds for barang alone, customers think I'm ripping them off.

Because too many RM80 installer on FB. People expect cheap. Using proper materials not part of the equation. Else I'd just ask customer you go buy the materials as per shopping list, then I come. Then they will appreciate that the components cost good money.

The switch is in my room, so i plan to replace the switch to 20a and add on the rccb 10ma, is that ok?

It's too much of hassle if to add another socket outside the bathroom and the wiring is hidden above the ceiling

Nowdays heater are 3800W with pump - 13a surely will burn after sometime. I usually use 20-25a Aircond switch and directly wire the heater to this plug instead of using a normal wall plug. Minimum wires size 2.5mm but 4mm ideal.

True.
I spec everything for my house and just ask them to name the price - things that I do not agree I will source my own part. For example the SPD RM500 ABB, he charged me rm1000+ for same thing. Not sure if his supplier gave him the correct price though.

Usually I am still okay if price is just the issue so at least we can directly go into negotiating - but what annoys me the most is the issue with their knowledge .. saying no such thing of 10ma for water heater and saying RCBO does not exist in Malaysia.


You can but if can please ensure it is protected from water splash - buy a transparent cover probably that covers it well. Make a habit to test it monthly for safety purpose.

If your setup is 2.5mm and using on good brand like MEGA or Caramay is okay - but anyway if not, and become too much of a hassle to change then you must make sure your setup along the circuit must be correct and right sized - 16A/20A MCB max.... - 2.5mm wire must follow the 2.5mm way of setup then would be good.

This post has been edited by davidlow7: Aug 25 2022, 10:35 AM

The instant water heater is normally at 3.3kW to 3.6kW power rating. So, current flow would be

3600/250 = 14A (worse case). Even 3300/250 = 13.2 A

The current 13A socket is not suitable. It still works for long time because there is buffer to its rating normally not specified. Therefore it works near its max rating most of the time. The rating is related to contact resistance between socket and plug. So, if the current is high, the heat will also generated thus weaken the copper property over time. The clamping contact worsen over time until the point it get burnt.

The best would be using higher rated socket and the best available is 15A socket. I've been using for more than 15 years with no burning sign and my heater is 3.3kW rated. As for the wire from the socket to the heater, the 2.5mm² is fine. It should be able to carry even 25A (or at worse 20A) at 60ºC ambient temperature, according to calculator I have here. Anyway, it is short cable.

The water heater has internal RCCB or ELCB, but test it regularly to ensure functionality. Adding 10mA RCCB provides redundancy just in case the internal one fail. Well, I don;t have one also

No wonder i saw a test button and reset button on the side of the heater, that make sense now 🤣

On 2nd thought, since you have base box where you mounted your current socket, why not just straight away use 20A switch and feed wire directly to the switch. Just need to make hole on the base. This way you have double pole switch as isolation and no pin contact issue over time.

The water heater built-in ELCB does not to protect human, it is only for the equipment. This had been highlighted numerously by our sifu @ceo684 which is correct so you are left with only the main RCCB to protect you in case of any leakage outside the water heater ..and usually the main RCCB at 100mA would not be able to protect you from death... at 30mA you would stand a chance to survive but not one without severe pain and injuriy to your body.

This is also shared by Showertec
This post has been edited by davidlow7: Aug 25 2022, 11:16 AM

Your water heater is rated at 15A while your plug is 13A, obviously it overloads it.

If follow ST guidelines, it has to be directly connected or using a proper certified connector and 4 sqmm cable.

In practice 2.5 sqmm cable works fine if your water heater does not exceed 20A.

Just take note newer water heaters today may consume beyond 15A, hence, even using 15A plug/socket (The round pins) is not advisable.

That's what I'm planning to do, already bought the 20a switch, just waiting to buy the rccb

I'll follow yr advise to add on a 10ma rccb, thanks again sifu, one question, since it have 2 pole for L n N, how about the Earth wire? Direct connect E to E?

There should be an earth wire that is connected directly to your DB Earth Busbar - so there will be 2 options depending on your setup.

Setup 1:
if you are using a 20A switch without another 3pin(round)socket --> then this earth wire will connect to your WH unit directly.

Setup 2:
If you are using a 20A switch + the 3pin (round) socket then this earth wire from DB will connect to your the socket in "E", while the L+N will come from your 20A switch.

This post has been edited by davidlow7: Aug 25 2022, 11:40 AM

I understand perfectly how ELCB and RCCB work. Why the big name in water heater manufacturer still use ELCB not RCCB? ST should make it mandatory to use RCCB for water heater, don't they?

How did people get electrocuted in cases of water heater? The casing is plastic and the hose is silicone rubber. Is it because the water heater uses ELCB not RCCB?

I can understand the point you are trying to make. especially for a more advanced user like yourself, but in reality things are always never going to be straight forward that's why I would advised against sending a message that the ELCB in each WH unit are safe and designed to protect human like exactly in RCCB.

Ability to understand the technicality of everything would help yourself in making an informed decision, but when it goes to the MASS then it is about making sure it becomes practical for people to understand in the most simplest manner possible.

You would never know what are inside certain manufacturers' units and the timeline that bought also came with it, and also the customization by users that would happen over time, such as the use of stainless steel rain shower to replace the hose set. Some people would be using very old units that might have different components in it - the truth is no one can confirms unless a test on each model would be examined - which is of course not possible.

What we know is - For sure following the setup for a dedicated RCCB 10ma would eliminate the uncertainties around.

This post has been edited by davidlow7: Aug 25 2022, 12:12 PM

The main problem with ELCB is more into the functionality of Ground wiring which maybe overlooked. The L and N wire if no connection the user will know immediately since device will not operate but for E failure no one will notice. This will not trigger ELCB in case the E circuit failed.

The new device that is more advance than the RCCB is GFCI. This will performs what RCCB does and also sense short between N and E. My company is producing this for a Europe customer.

RCCB and ELCB cost difference a lot. It may cost more than half to 3/4 of a RM200 water heater.
Since the onus is on the user/installation and not mandated (on the mfg of WH).. don't put in better.
After all most consumer only want cheap like a purchasing dept.
You give them good, not that they appreciate (they think we trying to rip em off); not many consumer will consider the quality of work and what they're missing. Only those in the line will be scared (the thing about people dont know what they dont know)..that's why I run my own home DB setup as stringent as possible. Nothing above 30mA on mains and each WH has a 10mA RCD.

ELCB covers connectivity to ground check.
But ELCB is not a replacement for RCCB.
ELCB if not mistaken is a mandatory item in WH that's why they all come with ELCB LED.
There's also AFCI too

Well, many electrical contractors charge too much but using low quality material. Most likely it is because they need to pay workers salary all year round and projects are not continuous all year long. For that reason, I also prefer DIY

I'm not sure about the price because I'm not in this business line. However, if you talk about the manufacturing cost, ELCB is more expensive to produce compare to RCCB but the RCCB perform better than ELCB.

I guess the main reason for ELCB in appliances is detect faulty appliances

Also boils down to where it's made and currency exchange.
ABB/Hager 10mA made in Italy or France easily RM150-160/ea
Cheaper one local made or Schneider around RM100
Cheapest one from PRC around 60 bucks IIRC..
but u wanna save money on the "safety belt" device meh? Especially its "one-off payment life insurance" as compared to whatever insurance every year pay a lot.. this one pay once covered for 20-30 years.


I also DIY because in that sense I know everything is fastened properly and according to spec or even some of the time, exceed spec (especially for short runs).. cable so cheap even for 4mm loose cut.. it won't break the bank. Its about not having to deal with melted wires or risk of house catching fire
For time saving and avoid breathing in plaster ceiling dust I also retrofit wago connectors for those LED downlights.. fiddling with screw connector is waste of my time when i can just clip unclip.

Hard to find clients that will insist to do it properly up to spec (safety is 1st priority) and don't mind paying (reasonable amounts).

This post has been edited by ceo684: Aug 25 2022, 06:30 PM

SG and Msia installations have this same issue of not-up-to-code old installations.

However, there isn't much awareness on retrofitting with 10mA per water heater OR to get the highest sensitivity mains RCD (30mA whole house) in MY.

In SG it is pretty common to see new installations with 30mA whole house RCD everywhere.
10mA for water heater still a question mark in older HDB. Not all have it retrofitted.

This brings up another can of worms - before renting a place, also check the DB box that it's safe to use.