Noted, does it mean, i have to trace the WH circuit, replace the 10mA RCD, right?

Btw, my WH comes with built-in RCD...would this sufficient?

Thanks!

Yes can direct replace the 0.1A (100mA) with 0.03 (30mA). Yours is single phase, so the main RCD it will be a 2P(oles) 63A 30mA type. This will be a direct replacement (same physical size as currently installed type)..The really fat one (RCD) is 4P (3P+N) for 3 phase wiring.

Good news, 2P RCD is still cheaper compared to 4P RCD.

For the MCB problem, you can get a same rating one as current (if faulty is C16 buy another C16 from ABB Hager Schneider to replace first).
All things AFTER main switch will be isolated as long as the main switch is off and verified with test pen.
Test pen also need to verify it lights up first, so as not to have false negative due to broken test pen.

Rule of thumb is when working with electricity, ISOLATE and TEST, TEST, TEST before touching anything.

Yes 10mA (0.01A) is the correct rating for WH RCD. Even more importantly for countries on 230V. For life protection I only trust the top tier brands. ABB / Hager 10mA come from EU.

Most water heater tend to be ELCB based (the one could be RCD but not sure how quality it is).. there are cheap RCD out there but for 10mA i would strongly recommend a top tier brand (ABB hager schneider); schneider RCBO just over 100 only; the rest standalone about 160-170/ea. Per ST guidelines, proper standalone RCD is still recommended.

This post has been edited by ceo684: Jan 15 2021, 11:15 PM

Thanks for the advises.

You mentioned "Yes can direct replace the 0.1A (100mA) with 0.03 (30mA)"....do you means i can replace the "hager 63A/100mA that i have in my current set-up?

I was thinking to trace the maxguard MCB C16/C20 that attached to the WH, replace it with branded MCB with 10mA or 30mA....will it served the protection purpose?

Btw, i will buy the parts and ask technician to help me to replace the MCB.

Any ideals what is the different for the maxguard MCB C16 and C20?

Yes, you are right, the RCD 10mA should be installed for WH, it was regulated in 1994.... but not many people is aware of this!

Checked my WH menu, there is a built-in RCD, but no specific on the spec of the RCD, not sure if it is 30mA or 100mA?

You mentioned "Yes can direct replace the 0.1A (100mA) with 0.03 (30mA)"....do you means i can replace the "hager 63A/100mA that i have in my current set-up?
Yes, replace this with 30mA main RCD (specifically 63A 2P 30mA type)

I was thinking to trace the maxguard MCB C16/C20 that attached to the WH, replace it with branded MCB with 10mA or 30mA....will it served the protection purpose? MCB and RCD operate differently (like seatbelt and reverse sensor of your car).
MCB protect against current overload (FIRE risk from cable overheating and the copper wont melt instantly but its the plastic insulation that catch on fire and so on that cause house fire).
RCD principle it operate when there is any current imbalance(whatever input current must = output current, this is normal condition. If 10A go in but 8A come out means the 2A must have got lost somewhere.. and that is what will trip RCD.. with a 10mA RCD >0.01A loss will trip. with a 30mA >0.03A loss will trip. That lost somewhere means a fault already.. whether leak here leak there leak thru human body is irrelevant..to the RCD current cannot "lost" one..same as bank teller if cash in drawer not tally with system means they need to hunt and trace every sen as any error means something wrong somewhere.

Just like seatbelt and reverse sensor both protect but they protect diff thing and operate differently, same goes to MCB vs RCD.

For RCD, it constantly compare the IN - OUT current all the time and if there is more than the acceptable loss (based on RCD sensitivity 10mA 30mA etc) it will trip.
So because it need IN vs OUT (Live vs Neutral) comparison to work, the (IN) Live one is pretty easy to determine since u off the MCB 1 by 1 to trace, and the one that (when MCB off) doesnt turn on the WH, that should be the Live WH cable.
For the (OUT) Neutral, in DB box all the black wires typically connected to the common shared neutral busbar. This one is more time consuming as u need to isolate one by one each N (take out one by one) until you find the one that doesn't operate the WH, that should be the N WH cable.
Of course do a double take and mark these (L WH) and (N WH) with tape or sticker. Then plug them back in and confirm WH works now. Successfully identified the WH L and N now.

These (WH Live) and (WH Neutral) will need to be connected into the same 10mA RCD (load side).
The (power feed) L and N on the 10mA RCD Line side, can be connected to Line L busbar and N common busbar respectively.

To answer your question.. since already open up the DB might as well replace the whole strip of MCB and RCD.
The RCDs are more pricey than a whole strip of 6ka MCBs.
Adding a 10mA RCD will need two slot (2-way) more space though.

Btw, i will buy the parts and ask technician to help me to replace the MCB.
I was thinking from a total overhaul POV.. since adding each WH 10mA RCD will take 2-way more than existing (hence need DB box upgrade) - can also consolidate all the SPD everything into one box *subject to MCB wiring being long enough* - they do sell 36-way boxes (2 rows x 18way) - https://shopee.com.my/EPS-EL02-(2-ROW-36-WA...6357.6805234786
OR
minimally invasive one, trace back WH wiring (L and N), replace that existing MCB with RCBO (in situ). RCBO take care 2 jobs (MCB+RCD in one module size).


Any ideals what is the different for the maxguard MCB C16 and C20?
One trip at 16A rating, one trip at 20A rating. MCB Sizing should be based on load and cable size. Usually it should be no bigger than C20 for 2.5mm (13A socket/WH) cable, and C10 for light circuit (1.5mm) but if its dedicated light circuit putting C6 also won't harm anything (extra safety) since your lights in totality for whole house won't exceed 1000W whereby a C6 for light circuit is way more than enough already.

Yes, you are right, the RCD 10mA should be installed for WH, it was regulated in 1994.... but not many people is aware of this!
Safety of electrical installation is taken too lightly in MY. Same old story, people maybe unaware, every year also come out in the news people die from WH electrocution. Even their 13A plug can be left hanging with the LNE inner wiring exposed for few cm instead of properly fixing up the plug to grip on the outer insulation


Checked my WH menu, there is a built-in RCD, but no specific on the spec of the RCD, not sure if it is 30mA or 100mA?
Seems vague to me. In the diagram it shows a RCD at the DB box Err on the safe side, this is cheaper (price of RCBO/RCD from top tier brands range from 100-170) than life insurance premium.

This post has been edited by ceo684: Jan 16 2021, 10:03 PM

Thanks for the details explanation.

I think i can identify which MCB for the WH, but a bit hard for me to check the Live-HW and Neutral-HW cables, unless i ask the electrician to check for me.

By changing the main RCD to 10mA or 30mA, does it means it is safe for using the WH, no need to change each MCB? But will it be too sensitive...and causing electric trip more often?

This post has been edited by clickNsnap: Jan 16 2021, 10:08 PM

For MAINS RCD change to 30mA Bao-Kah-Liao whole house
Yes, I did this before when refreshing my 1995 DB box.
Scenario: For mains RCD change to 30mA (current ABB/Hager models selling now) they have anti nuisance trip; I think Schneider also has it.

My personal experience in parents' house: It was on 1995 era ABB 40A 4P 300mA before this when we took over as 2nd owner. Now using ABB 40A 4P 30mA, no complains.
Result: No difference in trip problem or trip frequency for main 30mA RCD.

CONSIDERATIONS WHEN ADDING 10mA into OLDER HOMES with NO 10mA RCD
The thing about 10mA WH RCD/RCBO it will not work on shared neutral (10mA will always trip unless wholly dedicated L and N).
Just like company claim should only be for your own usage, you should not take receipts from next door diff company workers to claim into your claim submission, will trip finance_RCD

I face this problem before here, (my wiring was very messy as this is used apartment, previous owner do a lot of funny things, I even suspect the WH is also connected to ex-13A point or looped somewhere in the neutral)
Adding SPD and splitting shared MCB (2-3 wire into one MCB ) required more physical spacing.
End up expanded whole DB box to 36way also not enough (previously was falling apart elcheapo plastic box)
Then realised needed more than that so spill over to second DB box. 3 phase big modules really take up a lot of ways.

Solution was to run direct LNE cable from DB box to WH (so its always dedicated neutral), perfect.

CONSIDERATION WHEN REPLACING EXISTING (QUESTIONABLE CHINA MADE) 10mA RCD in NEWER HOMES
No issue just plug and play as WH Live and WH Neutral should already be on dedicated L and N.
Also easier since wires are identified already, just need to see which is load side and which is line side.
And for this (my own place) I went with big DB box (45 way) straight away to fit all the expansion upgrades like Type2 SPD and have enough room for everything (RCDs, MCBs, main switch, SPD)

This post has been edited by ceo684: Jan 16 2021, 10:43 PM

Thanks for the tips!

I will ask my electrician to take a look 1st, i wish the "bao-kah-liao" solution works for my house...just changing the main RCD to 30mA

It is time to improve our house...look look see see...where to improve, during MCO period...haha.

Many thanks again!

This post has been edited by clickNsnap: Jan 16 2021, 10:49 PM

Most welcome. Am operating mains RCD at 30mA (0.03A) whole house sorry for blur pic.

This post has been edited by ceo684: Jan 16 2021, 11:03 PM


Attached thumbnail(s)

when the flickering room light is off, is there still buzzing sound from the MCB?

"HI is usually used to described advanced anti-nuisance trip (protect against switching transients and harmonics).
Those with anti nuisance trip (protect against switching transients) for residential use will suffice."

Thinking to update the RCD, currently on 63/0.1(100mA.)

How do we know if the RCD 30mA are equip with the anti-nuisance trip?
Are there any regulation/mandatory on this RCD to be 30mA?
Afraid after installing the RCD 30nA will cause nuisance tripping 🤔

Thanks for your input.

a. Current models got datasheet, basically either ABB/Hager current model [not listed as discontinued] will be fine.

b.Yes, Electricity Regulations 1994, MS 1979:2007 and MS1979:2015 for protection of 13A sockets, and since this is the tightest regulation, it only makes sense to have a 30mA fitted for whole hse. Complete protection.

Would you drive at high speed without a seatbelt on?

c. To add on, not just mains 30mA [whole house] but you should get a 10mA RCD per each water heater fitted too.
I'll be more afraid of what happens in page 30 of
https://www.st.gov.my/en/contents/publicati...r%20Systems.pdf
rather than nuisance trip.

FWIW everywhere in AU, SG all use 30mA. I also use 30mA. Life protection more important. Good [top-tier] modern RCD hardly nuisance trip.

This post has been edited by ceo684: Sep 22 2022, 10:44 PM

Thanks fir the advise 👍
With the regulations for 30mA RCD, I wonder how can most developers get away with it?
Is it just a guideline or compulsory?

Will definitely change to proctect ourselves, since it's just a one time investment on our life.

See attachment pg 21


Those who know will spec out personal homes to be as tight tolerance as possible, despite high cost [sensitive RCDs cost more], for lives of loved ones are priceless - can't sleep at night if we did a half-assed con job;
those who cincai undercut job of coz spec as loose/cheap as possible to avoid rework calls [since less sensitive RCDs are cheap and trip way lesser]

This post has been edited by ceo684: Sep 23 2022, 09:24 PM


Attached File(s)
 ST_Guidelines_For_Electrical_Wiring.pdf ( 427.2k ) Number of downloads: 24

Is this brand Reliable?
Just install 0.01mA for WH and 0.03mA for wall socket.

Wondering can I use the 25A for water heater ?
Previously was just 16A as the wire are 2.5mm.


Attached thumbnail(s)

An RCCB does not trip on overcurrent. You should be running
Incoming power -> 16 A MCB -> This 25 A, 10 mA RCCB -> Water heater,
so that the MCB trips if more than 16 A flows, and the RCCB trips if there is a leakage approaching 10 mA.

Only an RCBO is like a combination of MCB + RCCB, and will trip if overcurrent or leakage current.

Can't comment on the brand, sorry.

This post has been edited by stormer.lyn: Sep 24 2022, 01:44 PM

Can't find anything related to the brand hence "no comment". The trademark is super generic nothing shows up on a bing/google search for "safety SRA2 RCCB"

Follow stormer.lyn post above is correct.
Personally, if own house I'd spec in only ABB/Hager because "you get what you pay for" also applies to components - you get VI type RCD; anything cheaper tend to be VD type RCD.

Appreciate it.
So should I change to RCBO, according to the electrician that our place does not provide a water heater point only normal power point and our electric point share with an a/c also.

Most probably will ask to change to a better brand.
Any brand with 16A RCCD or RCBO with 0.01mA for WH and 63A/0.03mA.
Can provide model no. for the VI type RCCD. Appreciate

So should I change to RCBO
--mostly boils down to space question only "DB box can fit the 10mA RCD [2module width] or not; since can fit should be no problem
--RCBO = RCD+MCB [like washer/dryer two in one - vs a washer+a standalone dryer]

Any brand with 16A RCCD or RCBO with 0.01mA for WH and 63A/0.03mA.
--ABB/Hager

Can provide model no. for the VI type RCCD. Appreciate

based on ur pics ur on single phase.

mains 63A/0.03A [30mA]
-- ABB RCCB/ELCB FH202 AC-63/0.03 (30mA) | 2 POLE (2P)
-- Hager CD263B = 63A 2P 30mA; or CDA263U

WH 10mA RCD [need to pair with 16A MCB]
-- ABB RCCB/ELCB F202 AC-25/0.01 (10mA) IEC | 2 POLE (2P)
-- HAGER CC225B 2 Pole ELCB / RCCB 25A 10mA

Excellent. Hope the electrician willing to change a better/reputable brand of RCCD.

Incoming power -> New(Safety) 25 A, 10 mA RCCB -> Water heater, Is this OK?

So should I change to RCBO, according to the electrician that our place does not provide a water heater point only normal power point and our electric point share with an a/c also.