At the home town house , the electrical water heater doesn't heat up as hot as usual since the heating knob at the middle would be enough but it's still warm or luke warm.
Since , call back home town , elderly doesn't know much about water heater safety neither do i since I am not in electrical field.
Also old 30 years housing doesn't have any dedicated RCCB or RCBO.Just the main DB MCB some kind of SMC brand.

1.The water heater is like over 10 years old with ELCB
2.Not hot even on middle
3.I ask them to take a picture of the MCB but the heater is quite high so i ask for the model and details
4.Possible to repair ? or change a new one ?

This is the National water heater brand , not sure how long was it .Anyone have any idea of this model ?


Right now , what I should to do for advice ? Currently , i am sure they doesn't know any good electrician who are expert in water heater except those random letter box name card.
Please help me with advice on which option in increase the safety on water heater ? I read some of the water heater thread but do not understand since i am deep understanding in electrical.

Dear Expert ceo684 , Momo33 , halcyon27 , Selene Yeo , stormer.lyn
Apologize and hope you all can help me on the urgent matter since I stop them from using the water heater for safety purpose.Beside need also find a new water heater.A cheaper one without pump but safety first by adding extra DB.

This post has been edited by Maxieos: Oct 16 2022, 07:26 AM

-Reserved-
Will ask for brand
The post limited to 5 user tag , hope you guys can give a bit of comment.Zot , FusionXY.

Not worth, can't find spare part, buy new one cheaper.

I would say buy new safer.

Labour to repair and new installation is the same thereabout.

This post has been edited by mini orchard: Oct 16 2022, 08:35 AM

1. How cold is the incoming water?
If not mistaken this unit is 3.6 kilowatt of heating only. If the incoming water temperature is below 24°C it will only produce luke warm water even already turn the knob to maximum.

2. There are still spare parts for this model but for your piece of mind you should buy a new instant water heater for your parents. Panasonic is a good choice.

But do check the temperature of their incoming water supply 1st, cos already 2 consecutive days my place also has been raining, so my heater also unable to be hotter than usual.

FYI Panasonic do sell a 4.8 kilowatt units for those staying in Cameron Highlands and Genting Highlands.

Baru asalkan selamat

Buy new nowadays water heater not that expensive

First of all, limit the volume of cold water. If your house pressure is very strong and you open full blast then memang lah it won't be cold. Try adjusting the pressure to be less strong first then test the heating unit again.


Also, that heater is not over 10 years man. That's 20 years... I have that one when I was a young boy haha.

This post has been edited by patienceGNR: Oct 16 2022, 09:49 AM

That smc is not a MCB, it's a rccb, the 100mA is the sensitivity of the rccb

I also got this type of water heater.. Usually i put it to near the full colour line to make ther hot...

DO NOT try to save and repair a water heater. You don't even know how good is the repair work. Other parts are old and might be about to fail anyway. It's time to get a new one than having the risk of being electrocuted!

Second, plug shouldn't be used as they are prone to hearing and melting. Electrical line should be directly connected.

Third, add a 10ma rccb for your heater. 100ma won't save you if there's a shock. Some street sifu will tell you 10ma too sensitive and not good, they are talking rubbish.

This post has been edited by pmaxv: Oct 16 2022, 10:08 AM

Or get a water heater with built in rcd/rccb

And yes those street sifu will tell you too sensitive a bit a bit trip lol

U rather trip or die?

Follow what others mention.
I also have the exact same water already more than 20 years.
Already replaced mine with Panasonic last year exactly on today itself.
Buy new one for safety, more than 10 years plus consider good already.
No point to save old appliances like water heater, jug kettle, microwave oven.
Better be safe then sorry. Sometimes the ELCB might fail to detect then electroluted

Ours one dead due to debris stuck inside the water heater as old model does not have filter to prevent debris being stuck.
The water becoming slow and the water flow sensor failed to detect incoming water thus power light not on means no hot water will be out.

I would recommend this model DH-3MS1MW.
If you cannot find this model then get the U Series type but a bit more expensive as it is a new model.

Consider changing instead of repairing. Electrical items cannot last forever, they tend to malfunction over time.

Since it's not functioning normally, just replace it.

I once tried to relocate my 6-year-old heater. The interior circuit board looked "charred" a bit, so I threw it away. Can't imagine the condition of yours which is easily 25 years old.

No point to repair a >10 year old equipment. Get a new water heater and get the installer to put in a 20A 10mA ELCB just before the water heater.

Only fcking idiots (unqualified electricians) will put an insensitive RCD.
Coz not they die ma "not my house syndrome"

10mA RCD is "accepted standard" globally.

Yes the Pana DH-3MS1 will be the push start workhorse (M series w/o pump)
Any more u are literally paying for plastic cover changes (black version M, or anything else that cost more).
The Pana water heater design is tried and tested liao.

DH-3N (N series) the fancy colouring will wear out and become ugly over the years (think car door handle)

I relocated mine from 2000 era into my apartment. But ours in good shape lah.
1. Doesn't matter how old the heater is = having a 10mA RCD is of paramount importance. Too many ppl died in vain coz spent "a lot of money on the heater" YET "RM0 on the life protection" .

2. A RM280 heater (DH-3MS1) amortised over 5 years only RM56 a year; but usually they last at least 10 years .. only RM28 a year!

Yup a new one is safer
RM280 heater (DH-3MS1)
RM160 for ABB/Hager 10mA RCD - barang only provides BEST protection if money not a problem
-- RM100 for Schneider 10mA also can lah IF budget really a problem
-- RM61 for Maxguard 10mA RCBO -- I consider this Maxguard 10mA RCBO at the very bare minimum acceptable equipment. Can't afford this please dont use water heater.

Sadly N series being replaced with U series.
Not available on their website already.

Specific to your case, retrofitting will be required.

1. Need to check whether the existing LNE lines from DB box to that point in the shower (currently the round pin socket) is of sufficient wire gauge (2.5mm is bare min). Best advise (to fool proof it for next 30 years - run a new set of LNE cables from DB to the WH point in bathroom in 4.0mm Mega Kabel - its cheap if you do exposed/surface conduit).

1.1 Assuming 2.5mm existing cables, you can only buy the 3kW class heater, do not buy a 4800W one, it will catch fire.
1.2 At the bathroom last mile (where the round pin socket goes currently) - use a proper connector like the Centon water heater connector. Because ST regulation say must be direct connection - not socket. Loose connections cause fires.

2.0 At the DB box - retrofit in a quality 10mA RCD or RCBO, per each water heater. This is your life insurance for water heaters.

3.0 At the DB box - change the mains RCD (the one for whole house) to 30mA. This is 2nd line of defence. In case the 10mA failed to trip - the 30mA will catch it and trip (like a fail safe). If your 10mA failed, and whole house one is 100mA or 300mA which I suspect is the case - there is no backup - GG.com because >50mA leak thru human body, sayonara.

Why so many upgrades?
RCD also wears out after 30 years.. springs get weak etc.. aiya even original 1985 proton saga also need to change many things by now in 2022 lor.

This post has been edited by ceo684: Oct 16 2022, 04:41 PM

Tell us how the connection will be?
Like which one put in DB and which one should put near water heater, etc...

Asking for myself and on behalf of others.

Where to install the rcbo?

In the DB or replace the water heater switch outside the bathroom?

All RCDs in DB box. This is supposed to be "professionally installed equipment".
Any registered wireman/wirewoman (at least PW1 or PW3 cert) will be able to do it.
Working in DB box 1001 things can go wrong so please call a proper wireman. Coz its impossible to teach online, this is not the same as plumbing where the worst that can go wrong is you get yourself all wet.

All "user servicable items" like the 20A water heater switch will be right outside the bathroom.

Salute to ceo684

Kudos to Sister ceo684

In short, buy a new reputable water heater for life sake

1. Definitely get a new water heater. That model is too old, not worth it to repair (but maybe keep it, and sell it to some museum or antique cafe in the future haha).

2. If the current water heater is not hot enough, check what's its power rating in kW (might be a 3.6kW), and get a higher kW water heater. These few weeks are rainy season, so water source is usually colder as well. If 3.6kW is not hot enough, u might want to get a 4.2kW to 5.4kW water heater, PANASONIC, CENTON, JOVEN should have these ranges.

3. Get a certified electrician to check and make sure all power connection are up to specs, including MCB, power cables (Suruhanjaya Tenaga recommends 4mm), STRICTLY NO PLUG+SOCKET CONNECTION IN THE BATHROOM (you can use the same junction box and replace it with CENTON SplashProof Connector as what @ceo684 mentioned, can easily purchase from Shopee here).

4. Use non-conductive hose / pipings.

Thank you sharing knowledge.

May I know:
1) why ST allows 100mA main RCD (or even 300mA as I saw in some houses) when >50mA leakage is fatal?

2) when RCD ages, as in spring weakens, will it be easier to fail safe (trip off) or it doesn't trip easily? I'm thinking that if it's the former, it's safer albeit mote troublesome.

for now
just buy any panasonic water heater with the ELB button on the front panel . / earth leakage test button .
pana WH have elcb for 15mA inbuilt hence not too worried about safety of this WH .
but you need to test the function / depress the button Monthly .

you need to test your SMC 40A RCCB at the DB box , regularly too as i see this is an old house /old DB box etc....
if you have budget then time to change this RCCB too.

ST recommend 100mA RCD / for whole house installed in the DB box.

some house use 300mA cos maybe they dont know the standard or got scam by the electrician .

2/ if the mechanical inside fail then it will not trip when you press test button.
if old RCD i would think the leakage current detect limit will be off .

1) It is not ST allow, it is because people want cheap and a black market of unlicensed unqualified "faux electricians" who know nuts exist

2) Do the price /30 years its already super cheap lah. Electrical safety kena question like FBI interrogation how to cari makan. It could actually be less sensitive due to metal spring lose tension.

This post has been edited by ceo684: Oct 20 2022, 01:29 AM

No, ST is not recommending specifically = 100mA whole house as the only RCD.

Like that, all the 13A SSO is illegal.

Yes I know can install 100mA whole house and another 30mA for 13A SSO.

But when MS1979 COP already mentioned maximum allowed tolerance = a 30mA settle all for whole house and fully compliant

Q: Why waste money with 100mA RCD whole house when it is largely redundant in 2022 scope of work - no more fluorescent lamps; waste DB box space
Or it is a ploy by RCD maker to sell more RCD?

This post has been edited by ceo684: Oct 20 2022, 01:32 AM

TS MIA.

Not missing but busy.

I apologize for not replying.The updates

1.Sunday no technician.So I suggest to increase the heater to 75% hotter ( basic 50% before it get less hot ) and spray into the water tub.I confirm that the water is not hot and I forgot to mention , the water flow is also slow.
2.Monday call 3 technician , all 3 said no need to put extra RCCB outside since all new or old water heater have Elcb build in.All 3 technician said something stuck cause it to get water not hot.
3.Tuesday , Call again to main joven and panasonic technician for repair but need to book the time next week and the cs said go to electrical shop and choose a model
4.Yesterday plan to go out and have a look for the model , heavy rain , didn't go out.
5.Today , see whether still rain or not at the evening. as what Momo33 said , buy water heater first , then only find a good technician.
All technician also didn't recommend to have an extra RCCB , i really don't know why as they said all buid in, no need anything extra.

As some technician told us better change but some said can fix.Most of them doesn't have cert or just normal electrical technician.
I also don't know which decision to choose where the water heater is less hot and water flow very slow.If water flow slowly should be much hotter.
Anyone know what is the reason of part failure when water heater not getting hot ?

Now finding a good water heater but budget not over rm400.
Any suggestion for DH-3MS1 and DH-3N series ?

Thanks , will reply to you all but I don't really understand much on those DB and model and brand.I need to research more into it.SOrry for not updating in time and thank you again

water flow weak most probably pipes are block partially due to old pipes / house , to confirm need to check if the water input to WH is strong
or the WH itself . the mesh filter at the input control may be clog of sand particles . need cleaning.
or the WH power control /temp control mechanism is faulty cos to old .

if your water input is strong flow then get the dh-3m , non pump.

pana WH do have 15mA elcb built in .
so a RCCB specially for WH is optional up to you /budget.


This post has been edited by Momo33: Oct 20 2022, 08:14 AM

Ts can unscrew the pipe connector to confirm the waterflow.

If is strong, water heater problem.

If slow, piping problem, then is not water heater. Replacing it wont resolve the problem.

This post has been edited by mini orchard: Oct 20 2022, 08:08 AM

yes , one can try use 30mA RCCB at the DB box.
the issue will be more power trips . as in Msia we do have many lightning storms . and if you are not home
the food in the fridge will go bad.

the thing about 30mA for 13 A SSO really how many house implement this . even in todays new houses majority
dont have.
so how did they pass the tnb inspection /CF and is it really necessary . i dont really know.


This post has been edited by Momo33: Oct 20 2022, 08:22 AM

Hi ceo. I've got a question on point 3 of yours. How do you add the 10ma RCD under the 30ma/100ma RCD? my electrician told me if I do a hierarchy level that will cause side effects. eg. they trip each other off. so he told me to install flat level instead. eg. the rcds are totally isolated.

they will not trip each other off.

example if there is leakage of 20mA in the WH , only the 10 mA RCD will trip.

Actually ST requirements are 100mA for lighting and 30mA for plug points (power points for equipment easily accessible by hand). In this case, 100mA main RCDs are acceptable, provided that you have 30mA to cover the plug points in addition to the main RCD. If there is only main RCD it has to be a maximum of 30mA, but ST doesn't really recommend 1 RCD for the whole DB.

Of course, this is in addition to water heater circuits which are required to be protected by 10mA RCD (dedicated).

Adding a 10mA RCD in cascade with a 30mA/100mA is not an issue. The device is meant to trip the power due to safety reasons, what may happen is that both may trip at the same time if there is a problem, which is more preferable to it not tripping when the problem occurs.

Doing it "flat" is of course preferable but will involve alot of work at the DB, which is dangerous if not done properly.

Both may still trip, due to tolerances of the device itself especially when 10mA and 30mA are quite close in rating. There is a proper way to do discrimination of tripping for the devices, but even without the discrimination it's still preferable to put them in cascade rather than not having sufficient protection.

ceo684 Is this the way to find certified electrician to check and install apartment DB and wiring?

https://ecos.st.gov.my/ms/web/guest/senarai...aftar-elektrik-

If the certified person do the job, then ok. If he send his foreign worker, lain cerita if he dont follow-up on the work done.

This post has been edited by mini orchard: Oct 20 2022, 01:29 PM

Hi Kytz, thanks a lot for your reply.

For my RCDs, my electrician just daisy chain them from one RCD input to another RCD input. Ended up quite a long chain cause I've multiple RCDs. Is that dangerous?




As for discriminate tripping, I think this one really need proper sifu. I think 99% street sifu don't know this. Mine also don't know.

Physical installation of electrical circuits can get quite misleading. If the cables are terminated in a daisy chain as per your picture, that is a parallel(flat) installation instead of cascading. Because the looping is happening at input of RCD only.

For example in below case the RCD are separate and will only trip 1 RCD if a fault happens at A / B / C / D respectively.


But if cascaded like below any fault in B may trip both RCD, but a fault at A will only trip the bottom RCD.


It's considered cascaded when output of the RCD is connected to the input of the next RCD, as you can see in the picture above.

In your case, if all 4 RCD are installed in a cascade, it's not dangerous but likely to be redundant because any fault at the end of the RCD will likely trip all of them, unless there is sufficient discrimination between them. RCDs are protective devices, so they don't introduce danger through their operation. But if RCD is not installed or is faulty, then the lack of protection from the RCD can be a hazard instead.

Yes indeed you're right. Mine is linked parallel. Not cascade. Which I thought might be dangerous cause if the 10ma RCD failed means no more protection. So was wondering if I should change it to cascade.

Actually devices that can cause safety hazards like water heaters already come with built in RCD nowadays, so it's not necessary to cascade multiple RCDs (as long as all DB circuits are properly protected already with the correct ratings).
Rather, it's recommended (and also more important) to test the RCD regularly instead to ensure that protection is intact. Some water heaters even allow you to test their RCD.
Because like what ceo684 has mentioned, the RCD will fail someday, and the only way to find out is by testing them.

might be easier to add single 10ma rcd (with cover) next to heater switch outside bathroom.

Much clearer. Thanks a lot for the explaination Kytz! At least now I know my DB is proper. Have done a lot of homework with DB. I've got 100ma for non-socket (eg. lights), 30ma for sockets, and 10ma for heaters. And to prevent lightning tripping I've added surge protector device (SPD) into DB as well. So far so good. My place has never tripped before even with lightning. Very reliable.

Actually not a problem.. 30mA built in modern day with anti nuisance trip trips very little

Correct. It should be tested as part of every new year/CNY routine maintenance.

This is a plan B solution, but for ease of troubleshooting it is safer to put everything at the main DB.

This post has been edited by ceo684: Oct 20 2022, 09:37 PM

Not many - its common in retrofitted and new build in SG
But in MY.. new builds got put but mainly China brands to save cost
Rarely you will get Schneider nowadays even for half million dollar place

30mA RCD, whole house (sum of all L - sum of all N return = acceptable losses)
Branches out from here to a bunch of little MCBs.
The 10mA is just for WH's own single L and single N. Input=output = acceptable losses and won't trip. IF the WH N is shared that means:
1) Installation is wrong in the first place
2) Useless for purpose of RCD, forever trip.
3) Most likely because it is not a dedicated LNE run from DB box to the WH unit.

Impossible they will trip each other off unless the WH circuit is shared neutral.

Correct.
And if there's a leakage of 20mA in a socket or light outlet unrelated to WH circuit, the 10mA will not trip.

No, this is acceptable.

Mana ada WH with built-in RCD.
ELCB got lah.

RCD is god tier protection (think of it as modern airbags)
ELCB is antiquated retired era stuff because "what if leakage don't leak nicely through Earth" aka leak elsewhere e.g. humans = don't t

Actually ST recommends monthly testing for RCDs, which i believe most people do not and will not do due to the hassle.
But if someone were to practice it, having all the RCDs in the DB would be an easier task than testing DB and all water heater switch locations. So the recommendation to have them in DB rather than at the switch is a sound one.

RCD is just a name for a class of devices that protect people against earth faults. What you probably mean is RCCB which are common used electrical devices.
Higher range devices are ELR and EF relays, which are overkill for domestic use. (for example RCD = vehicle, RCCB = car, ELR = lorry, EF = trailer)
That said, water heaters should be using RCD nowadays since ELCBs are no longer allowed due to obselete technology(voltage based) compared to RCDs (current based).

Thanks for the explanation on RCD and neutral line. They are definitely very informative. I like how you explained the current going in and out must be balanced. Now I wonder if my neutral is shared. But that one got to ask my electrician. So far no tripping yet.

Looks like you have all advises you need on water heater. I was away from PC for at least 2 weeks now

On old water heater not being hot, very likely that there is calcium carbonate build-up inside the copper piping at the heating elements. This will cause heat transfer to the water less efficient and waste of energy. I'm assuming that you are comparing the heat setting when the heater was new compare to how it is performing now. It is good idea just to buy new water heater.

Like one said, when incoming water is colder than usual like during rainy season, you do find that you need to turn the knob higher to get more heat.

This post has been edited by Zot: Oct 25 2022, 08:33 AM

Last week i call to those electrical man , not as details as yours but they did said something was stuck and said can be fix and clean.

1st , I don't think it's because of rainy season , it's more like it's not hot.Example yesterday was fine at 50% tuner knot but today 75% only achieve the same temperature as 50%.It's 25% difference.
It's comparing yesterday and today.Just 1 day the difference it too wide.

I haven't go and check the piping but I am sure the water flow speed is same from yesterday and today and only the changes is the temperature need to set to 75% compare to yesterday 50%.
If the water flow flask is faster , I think need 99% to get 50% temperature.

What could be the reason ?

Possible the temperature control knob spoilt.

Now that you mentioned it is intermittent, then it is most likely that the potentiometer (variable resistor) that control the temperature setting is bad. Over time the brush contact and the carbon rail gets bad giving this problem just like amplifier volume control. I'm quite certain an old (even new one) is using this part as setting control. This is not expensive part, probably around RM10 (so long never buy this )

If the piping stuck, the water flow would be slow, thus water gets hotter not cooler.

Update , check the piping , nothing wrong.Very strong the water flow in as usual of long usage , heater likely about 50% of the flow out from the shower head.Maybe due to long usage.
If lower stream flow will get hotter but is cooler just within 1 day ago.

Possible but need to check by those electrical man.Is it safe to ask those electrical store to check ? I don't think they are certified for water heater.
Now using back normally.Just have to turn the knot higher 75% since most of the electrical man said it's safe , just something stuck and water flow really getting slower than before.
Last 2 week still can get 50% flow out but this week only 40% flow.Don't really know what happen.

Should change or should fix ? Still looking for a budget panasonic unit without pump.Not over rm400 + installation.