Hi all

Would like to ask, does anyone install individual RCCB outside the bathroom on each of their water heater?

There is a central RCCB at the DB box in the living room, but I've read somewhere for water heater it's best to install RCCB nearest to it possible. Was thinking of installing individual RCCB and ELCB as well, but have read that if you have RCCB you don't need ELCB, and some recommend MCB + RCCB.

Already install MCB for each of the AC outlets and the oven.

Your advice is highly appreciated.

Maybe talk to these guys as shown here.

Your intention is correct...layering electrocution protection
MCB 100ma electrical fire protection
Water heater circuit 30mA RCBO residual current breaker and overload protection (layman calls it rccb but technically it's rc+o breaker)
Heater appliance ELCB built in. Newer ones also have 10ma RCD.

Some may add 10mA at the heater master switch also for added protection due for hook on contact when electrocution caused spasms that the user is unable to let go of the energized device.

The reasonable protection principle is redundancy....in case even the protection circuitry fails over time, there is another along the circuit to back it up. Just don't overdo.

The other is to engage a qualified electrician to check the integrity of the circuit at water heater after installation. Or a renovation that touched the bathroom and may have perhaps involved the water heater. A checker auditing an installers work. Usually the head electrician will do that. You never know...and don't want to find out the shocking way.

Also look up isolator barriers which are now mandated for storage water heater installations. The company that produces them is called showertec. And also non metal type shower hoses.

This post has been edited by halcyon27: Apr 8 2020, 10:51 PM

From ST guidelines ..

The recommended 4mm2 wire for 20A mcb to Aircon & water heater..

I suppose if you install new might as well use the recommended sizes.

i used 2.5mm2 for water heater and aircon when i renovated yrs ago so better confirm with your wireman if you want the 4mm2..

Agree ..

The RCBO combines both mcb and rcd in one device..

For water heaters better use a 10mA RCD or 10mA RCBO per ST guide.

RCCB (residual current circuit breaker) & RCD (residual current device) is the same thing and operates via trip relay current difference in mA betw live/neutral. No need earth wire to operate. Installed in DB..

ELCB (earth leakage circuit breaker) operates via voltage difference and needs an earth connection to operate..which is factory installed in instant water heaters cause cannot let the leakage current electrocution risk. So a low Impedance earth connection is important.

old houses sometimes have them (big black fuse switch with a yellow button) but regulations now is RCD's ..

WHOLE HOUSE
Recommend 30mA as little use to put an insensitive RCD unless you run huge motors (industrial) use.
According to Hager, shock exceeding 50mA is lethal.

Refer page 2 -  Technical_Handbook_10x15cm_English.pdf ( 3.41mb ) Number of downloads: 324


WH 10mA RCD
RCD 10ma need to be combined with the MCB 16A or 20A depending on your load amps of water heater.
There is no requirement to position the RCD outside WH. In DB box also same protection as the RCD work on differential L-N. If 13.000A incoming on L, at least 12.990A must return otherwise it will trip (current loss = fault somewhere).

You can choose either to add on RCD 10ma + combine with MCB,
or
RCBO (all in one) device - RCD+MCB in one slot (eg Schneider)

They cost about the same..
EU made ABB or Hager RCD 17x-19x bucks
CN made SE RCD is about 105
CN made SE RCBO 175

Recommend match back the brand you have in your DB box unless its some local made/CN stuff that doesn't get international certification.

Do note 2P RCD 10ma usually take up 2 more slot in DB box. Whereas for the RCBO you can just replace MCB with it directly.

Also need to identify which is the neutral wire dedicated for WH circuit.
In my new place built 2018 no problem they actually put in some china brand RCD but it is combined 40A 10ma for two WH circuits (which even ABB, Hager unable to produce such model). I replace with ABB 10ma RCD and split to two circuits/two RCD 10ma (i.e. dedicated RCD to one circuit) as they should be.

For my old place built 1995 i add in RCD 10ma keep on tripping when on WH. WH no issue with 30ma main RCD. Suspect wiring problem with original 1995 wiring so I run dedicated line to WH from the RCD 10ma in DB box then it was OK, since its MCO I only have 2.5mm cable but it works fine for temporary solution.

Aircon load 4-7A only for 1-1.5hp typical operating load.
WH is the one that heat up wires as typical load is 13.7-16A depending on power rating.

This post has been edited by ceo684: Apr 9 2020, 04:24 PM

i have RCBO just before my storage heater. But honestly, how many times you would test it in 1 year if you were to put it just before heater?

Maybe once a year should suffice if it's a good brand and not some kind of questionable CN brand..

schneider brand..
but as i recall, those in DB, need to test like once a month

What does WH means

water heater

Planning to replace replace old DB in house, currently only ELCB no RCCB.

Good idea, but it's troublesome to change to bigger DB Box and find the neutral wire dedicated for the water heater and need also separate the neutral bar for just water heater.
For simplicity i just change the socket or plug with built-in RCBO according to usage amphere. All of my water heaters and air conditioners are with RCBO either with socket or plug. Much easier

I have this 10mA but only 13A for water heater.



This post has been edited by amco: Aug 29 2020, 03:28 AM

That may work for aircon but WH at 3300W / 230V = 14.3A, 3600W = 15.6A which is a fire hazard to knowingly overload the 13A socket.

Schneider 1-DIN module RCBO is available so it is just direct replacement of the WH MCB in DB box.

This post has been edited by ceo684: Aug 29 2020, 03:48 AM

Actually, I am using China's plug & socket which is 16A for water heater with tank. That 13A is suitable for AC and tankless water heater.

What brand is that? Where to buy

Shud use sirim approved sso etc or later difficult to claim insurance if incident happen

I don't think it's suitable for water heater since normal running already exceeded 13A.


The correct one should use 30mA for whole house RCD, and 10mA RCD specific for each WH circuit as per ST guidelines.

can anyone recommend an installer for external rccb ?

This post has been edited by babybaby1988: Apr 19 2021, 11:28 PM

Well, it is supposed to be inside the DB box.
Any qualified electrician will be able to handle the installation of 10mA RCD.

Generally if theres enough space in the DB box for 2 modules ("fat RCD") then no problem to add it in, else may need to consider using slim 1 module RCBO instead. U can take a pic of the DB box and show us for better commentary. No need to open until can see wires. Just the user accesible portion will do.

There may be false tripping if your WH circuit is not dedicated circuit but running on looped (shared) neutral as the 10mA RCD is a highly sensitive device.

This post has been edited by ceo684: Apr 19 2021, 11:03 PM

attached is my current box, its messy as i requested my electrician to change all fuse mcb to trip mcb, but somehow my autogate and bell stop working and he cant seems to figure out how.

So i asked him to stop work and tmr another electrician will come.

So i told this new electrician i want RCCB outside toilet and i am not sure he understand what i want so he said he will come and see first


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Oh dear. Best to get the new electrician to do complete overhaul change all the MCBs to one brand (ABB/Hager). The MCBs around RM7-8 bucks each only at the electrical store.

As you can see, between the taller ones and the shorter ones there are physical differences. This is a very dangerous situation as it is a loose connection (can catch fire) for the top row of short Hager fuse boxes.

Judging from the age of the whole setup, it is likely that the wires has broke internally for the one that powers your autogate (internal injury of the cable).

Normally we will advise user to turn off the questionable circuit until the electrician comes - but in this case there are alot of LIVE WIRES hanging around with masking tape as insulation - so please do NOT touch it at all

This post has been edited by ceo684: Apr 19 2021, 11:49 PM


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You absolutely cannot use a shared neutral through a RCCB/RCBO.

Tankless water heater has to continuously heat the water, unlike tank type. The only reason the socket still survive is just because the heater setting was not not full power, perhaps.

Continuous heat on the 3-[in 13A plug will soften the clamping brass in the socket, thus making contact poorer leading to mere heat generated. This is how most fire get started in houses.

I believe if the N is shared before the RCCB, it is still okay. Not between RCCB and device being protected.

Yup, as this 10mA is for WH circuit only.

Whole house one still return to neutral common link so no issue for the whole house RCD.

Prev owner contractors did funny things for connecting the WH. I pulled new dedicated cables for the WH and all good

Thanks ceo684, finally got someone to fix back everything and change the mcb.

I plan to pull new wires from dbbox since i have shared heater and ac on all three bedrooms upstairs.

always have to off ac before use heater. so far no issue, just troublesome.

Any electrician whom u can recommend or u able to do?

Your new electrician should be able to handle?
Since new wiring (new set of LNE cables) being pulled it may make sense to procure the material yourself and ask him to come to install as labour only if agreeable and also it will save some cost lah.

Ideally, following ST guidelines, core scope of work will be
Pull a new set of 2.5mm² LNE cables for each AC unit
Pull a new set of 4.0mm² LNE for each WH unit
Add in C20 MCB for all the above circuits
Add in 10mA RCD to the DB box, one RCD for each WH circuit
Add in 20A double pole WH switch for each WH circuit outside bathroom
Add in 20A double pole switch for each aircon

Additional nice to haves:
Whether to conceal (need extensive hacking) or just run surface mounted PVC conduit (no need extensive hacking, minor hacking required) will be a price+aesthetic consideration.

Replace whole hse main incomer from switch fuse and old 100mA RCD - to new whole hse RCD 30mA + new whole house MCB (40/63A depending on existing cable size)

This post has been edited by ceo684: Apr 20 2021, 06:36 PM

Cos he doesnt do hack/conceal, only do casing

But i manage to find another electrician already, also prefer not to do hacking so i said will have to find some contractor to do hacking first

So i got quoted 3550RM without hacking for:-

a) install second DB at second floor
b) pull 3 wires for AC & switch
c) pull 3 wires for WH & switch
d) pull 1 wire for water pump & switch
e) pull 3 wires for socket

reasonable?

roughly circa 2100 for the electricals; and the rest will be the hacking work.
Sounds about right.

3550 is just for electrical, without hacking

btw can we change the neutral and live for rccb?

The electrician already changed the whole DB Box and mcb but didnt change the RCCB cos he said still can use but still charged me full sum .

I just ok that time, but now i bought another hager RCCD and think just install myself.

The new RCCB stated that top left no. 1 is live but my old RCCB the top right is live instead and the wire not long enough if wanna switch.

cannot.

with a distribution board so messy............i would change and redo everything

This post has been edited by slimey: Jun 9 2021, 06:14 PM

You need to plan out how to reposition it. When there is limitation of wire length, this becomes tricky.
I've done replacement of DB for such hangmen tight wires that it may require some creative placement (to ensure everything can be connected).
For the wiring that came with the house.. that one no comment la can't do much; but for new wiring enough slack inside the DB box is important so you can configure accordingly.

Not sure how the NEW DB (current condition) look like but from the OLD BOX you can isolate the whole house off by disabling the fuse marked with Danger High Voltage (pull out the fuse and put it safely away on a table).
The incomer will be a problem to shut off but if you can shut off the whole house using the fuse (pull out) then you can work on the downstream components AFTER it.

Your new RCCB (30mA) can replace the existing one (i.e. second module) of the OLD BOX pic AFTER you have isolated the power.

Ref OLDBOX2 pic:
Busbar and 16mm² mega kabel pigtailsin the correct RED/BLACK colours can be purchased as loose cut (by meter).. LINK (Loose cut 16mm)

This post has been edited by ceo684: Jun 9 2021, 08:43 PM


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Oh looks like my old setup the live is on RCCB top left, in my new setup (see attached pic), its on top right, so it means no issue to switch from left to right?


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Whoever did this should be banned from working with electricity.
The original (OLD FUSE) is 40A (sized for 10mmsq cable). Cannot suka suka replace with 63A breaker without changing ALL the wire to 16mmsq.
Should be fitted with C40 (NOT C63). 🔥🔥🔥🔥🔥 risk - cable all burn but the master MCB will not trip.."haven't overload >63A mah!"



You can park the new RCD at the far right and just extend with new pigtails.


I see the new one also 100mA Should return it and request to change it to a 30mA RCD instead as 100mA whole house is NOT up to code.
A single phase 40A 30mA RCD is not expensive. It make a world of difference between a 30mA or 100mA if there is a fault situation passing thru a human.


For further reading can see BEAMA (UK/BS standards) on RCDs.  BEAMA_RCD_Handbook__Dec_2010_.pdf ( 4.78mb ) Number of downloads: 51


Only in Msia lives are cheap- we still sell 100mA and 300mA openly






Unmodified file rotated for easier viewing


This post has been edited by ceo684: Jun 10 2021, 12:14 AM

Hmm already buried all the wires into wall can the electrician uncle just pull the cable out without hacking?

I was thinking about 30mA RCD too but when he tried to install a 10mA RCD at the water heater plug downstairs, it keeps tripping. The plug point has looping (to another 4 sockets which i am not using except for a socket for a hood) which causes the tripping according to him. So to be safe i thought just used back the original 100mA since no tripping issue.

The electrician also install new DB upstairs (as attached). Anything i should ask him to change besides to change the 10mm to 16mm? The water heater cable he is using 2.5mm instead and he said trust him no issue one even after i show him the ST guidelines, i suppose should be ok right since my water heater is only 15amp. Not an easy uncle to deal with, even after i bought 10mA RCD and asked him to install, he refuses saying ppl will laugh at me. Only agreed after i showed him the Electricity Regulations.


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Personally 30mA whole house will be fine since total amps IN = total amps OUT regardless how it is looped after that.

I run 30mA whole house myself no issue.
My parent's place also had this same problem where the WH circuit was shared with other things and its NOT dedicated. 10mA always trip. Resolved by running dedicated LNE circuit to the WH.
The difference is that the SINGLE circuit 10mA RCD had "unexplainable and unaccounted for amps from other devices" that the 10mA cannot account for = trip first talk later, save life more important.
Whereas for WHOLE HOUSE 30mA.. as long as total amps IN = total amps OUT (since there's only one IN and one OUT cable back to TNB meter) it will be fine, even high sensitivity 30mA also OK.

Anyway, congrats for putting in the 10mA RCDs for better electrical safety.

The difference is in 10mA WH circuit:
Even in cases where the WH circuit is actually shared neutral and trips the 10mA (because the neutral also contain other appliances' return so its imbalance with the incoming amp), this will not affect the whole house RCD.


This one can be solved by (a) correct way i.e. running a dedicated LNE circuit to that WH itself, as per code, without looping or
(b) use dirty trick (not so code compliant but likely to work without extensive hacking all over) is to install RCD as a spur i.e. AFTER the 20A switch (load side) and BEFORE the WH, so only that particular line going to the WH is balanced amps between incoming and outgoing.

Regarding the 63A MCB used on 10mm wire..
Changing the 10mm to 16mm will be expensive. In this situation, since your 63A will never trip before the 10mm cable is overloaded, the TNB cutout fuse will be your Plan Z overcurrent protection (between TNB meter to DB box) since that should still be on original 40A fuse.
The difference with MCB vs fuse, one can be reset in case of overload (just flip the MCB back on) whereas a fuse once blow already it need someone to buy a replacement, and that replacement fuse will not be available fast if the electrical supply store is closed.

Regarding 2.5mm cable used for WH circuits;
Should be OK-lah with 2.5mm for WH if its just 15-16A load, within spec of the cable, as long as its all 3kW class heater (3xxx W). You cannot install those highlands model with 4800W using 2.5mm cable.
2.5mm can withstand 21A safely.

That uncle cannot explain why these happened leh.. nobody is laughing



This post has been edited by ceo684: Jun 11 2021, 01:33 AM

The cutout fuse already blown once when I tried to plug in a old computer, so TNB came and changed to new one at 63A

So i should just use back 40A should be enough ? Change everything to 40A since my wiring all is 10mm to the second DB also

Normally, a fuse is sacrificial i.e. rated lower than the cable to protect the cable from burning up.
The other way, cable will burn up first to protect a higher rated fuse from blowing.

The TNB to main DB (incomer) is 10mm also?

Having four water heaters on at the same time is 16Ax4, without adding on anything else. Upsizing fuse need the cable to be upsized accordingly as well.

Tnb to main is 16mm at least I think.

Anyway I asked my electrician to change to 40a main switch and 40a rccb 0.03A. But even with full load of 51a tested using clamp meter, the thing doesnt trip? Something wrong ah? But the cable very hot though, almost 45 degree celcius compared to ambient of just 28 degree

The main switch need to be C40 MCB for it to trip on OVERCURRENT FAULT exceeding 40A.
Note: Just plain switch (isolator) without OVERCURRENT protection (ie No MCB function) does nothing to protect for OVERCURRENT.

When will MCB Slow Trip
In this case 51A > 40A its a sustained overload (MINOR OVERCURRENT FAULT) and it should "slow trip" using thermal trip within few mins.



I'm assuming you got a hager C40 P/N MU240A installed.
According to datasheet, https://www.hager-me.com/products/energy-di...u240a/30368.htm
min/maxi threshold value of the AC thermal operation 1,13/1,45 In (meaning between 1.13x40A and 1.45x40A)
for the 51A (divided by 40A rating) is around 1.27 In
this means a time to trip about 500 seconds based on Hager MU datasheet

‐-----
When will MCB Fast/instant Trip
(It will do a "fast trip" on the magnetic trip only if there is a SHORT CIRCUIT/MAJOR OVERCURRENT FAULT).

-----
RCD working principle is DIFF from MCB

For the 0.03A RCD yes this will be instant trip for CURRENT IMBALANCE (LEAKAGE PROTECTION).
The 40A on this unit is an indicator on how much total current can be safely monitored..but this RCD does NOT & will NOT trip in case of OVERCURRENT (which is MCB job).

RCD only measure "I-in = I-out + (tolerance of loss x up to 0.03A)". If the loss x higher than 0.03 (eg 0.032A) it will trip because "something is missing somewhere".

This post has been edited by ceo684: Jun 19 2021, 03:11 PM

Ahh no wonder.



Urmm lets say now my current usage now is 50A and then there is a leakage of 0.1A somewhere, will this 40A 0.03A RCCB trip?

For RCD it will trip.
Main RCD max current rating (40A part of that 40A 0.03) should match or exceed the main MCB rating (40A).

Please help me to check if my house wiring is correct.

My 3600W water heater shares a 16A MCB with the lights/fan in the kitchen, bathroom and 3rd bedroom. From what I understand light points use 1.5mm wires, so are the wires being overloaded now?
So far no problem. The heater was fixed 5 years ago by the shop people.

Another thing, all my light points use 16A MCB, while sockets use 20A. Should I change the 16A MCBs to something lower or it doesn't matter?

Lights should be C6 (6A) for safety. I don't think the installer would ever use 2.5mm for light circuits.

MCB must be rated lower than the cable safe load.
I suspect the WH is running on 1.5mm if its tapping into the light circuit if the WH circuit was not originally built in (wrong).

Shop ppl wont care.."not my house syndrome"

This post has been edited by ceo684: Oct 17 2021, 10:23 PM

This confirms my doubts. I wanted to DIY replace the heater but saw all these mistakes.

One more thing. I have another water heater, this one has its own circuit and is using a 16A MCB. Everytime the heater is used there's a buzz coming from the MCB. This has been going on for over 7 years. 2 years ago I changed the water heater to a new one and the buzz still happens. The installer said it's normal. Is this really normal? I suppose I can get the MCB replaced as the next troubleshooting step but keen to hear your experience on this.

Weird sounds are indicative of overload (close to redline) or loose connection.

What MCB brand are you using? It'll be good to check your cable sizing whether 1.5mm or 2.5mm...the former looks very thin. You can off the whole DB to check safely. The cable going out from MCB controlling WH should look like the sockets one..NOT like light circuits.

MCB brand is UMS.
Wires are 2.5mm and the screws are tight.

I think I'll get a wireman to pull new cables to both the heaters. Maybe install RCBO also.

Tumpang tanya
House rccb trip few times lately thunder
Notice the plastic part cracked
How much normally is the charge to replace it ah?

Depending on you're 1ph or 3ph supply, and how many amps. Take a pix and post lah.

Residential not all single phase ka?

I use 3 phase at home. The pricing of the device also depend on rated current. Hence if you're talking about single phase RCD, e.g. from ABB.os its 77 for 40A 30mA and 127 for 63A 30mA materials only

This post has been edited by ceo684: Nov 6 2021, 12:13 AM

Maybe ur house bungalow lo
Mine just normal terrace house
Add labour around 100?

Wah landed!
I stay in highrise.
Long time ago supply only 40A per phase due to wire size small. So not very useful, hence prev owner put in 3ph so can use up to 120A.

U supply the parts yourself will be cheaper than asking the electrician to buy for you..But to get the right part w/o pic of ur existing is hard..err on the side of 63A 30mA 2P RCD. then get an electrician or wireman to wire it up should cost around there. For plug and play replacement you can shop around FB..some are pretty cheap on labour. My usual sub con costs from 200 to show up.

Ok thanks
Got it done 180 with ABB
Fair deal i guess

Hi All,
does anyone know if water pump require a RCBO protection as it also dealing with water ? my current water pump has a dedicated MCB without RCCB, it relies on main RCCB with sensitivity of 100ma.

Here in MY whilst the appliance is not in a wet floor area, it won't be covered by ST reg w.r.t water heater. But if its outdoors then should have at max 30mA RCD.

b) Regulation 36(2) of the Electricity Regulations 1994 states that for
a place where the floor is likely to be wet or where the wall or
enclosure is of low electrical resistance, protection against earth
leakage current must be provided by a residual current device of
sensitivity not exceeding 10 milliamperes;
c) Regulation 36(3) of the Electricity Regulations 1994 states that for
an installation where hand-held equipment, apparatus or
appliance is likely to be used, protection against earth leakage
current must be provided by a residual current device of
sensitivity not exceeding 30 milliamperes;


Over in UK - https://www.electricalsafetyfirst.org.uk//g.../garden-safety/ it is recommended to fit an RCD for water pump.

In your case..I would suggest to change the 100mA main RCD with a 30mA RCD in the event rainwater drip in onto the pump during thunderstorm. Then it would cover all bases including your 13A sockets.

Modern RCD from ABB, Hager come with anti nuisance trip feature, it will not nuisance trip much compared to those sold before 2000, about 97% reduction.

thanks for responding, my water pressure pump is located on ceiling and covered by roof, hence it is at dry area.

do you still see a need for a RCD for extra protection ?

many have talked and discussed that RCD is mandatory for WH, little is talking about water pump here in malaysia.

on your recommendation on changing the main RCD from 100ma to 30ma, would it be too sensitive with unnecessary trips ?

i see many electrician uses 300ma in main RCD.

What is the likelihood the roof leaks from thunderstorm/strong wind esp in older homes, and causes the pump to be flooded?

RCD has dual function to protect life, and protect against fire.
Assuming only a single unit (main RCD) is installed, 100mA you already breaking Electricity Regulations 1994 as all the 13A sockets can kill humans at 50mA.

Itu electrician qualified or not? You are not running a dodol machine at home that will trip a 30mA on normal startup.

Nobody in their right mind put 300mA in residential. In SG and UK, everybody put 30mA for residential. Maybe Malaysia got stronger human than them can sustain 230V currents lah..

I personally use all 30mA.

As mentioned, modern RCD has anti nuisance trip so it does not trip on false alarm like those made before 2000.

This post has been edited by ceo684: Jan 13 2022, 02:24 PM

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/viewer.html?pdfurl=https%3A%2F%2Fwww.waterpump.co.uk%2Fmedia%2Fwysiwyg%2Fmanual%2F5711497234216.pdf&clen=6523985&chunk=true

saw this from grunfos scala2 spec doc, they do recommend to install RCCB with less than 30ma.

Recently upgraded to 3 phase for my house reno.
The contractor say this device the higher the better.
True?

Edit: found out mine is 300mA

This post has been edited by BL98: Mar 29 2022, 03:34 PM

The lower of the trip current, the higher sensitivity of detecting current leaking.

300mA better dun put la. Confirm six times killed, then only trip

The higher the better for them only because 1. Lowest price (lousy sensitivity is dirt cheap on 3phase) and 2. very hard to trip (no callbacks from owner). Which is ok for industrial use but at home, what good is human dying 6 times over ☠☠☠☠☠☠ before it decided oh ok..lets trip.🥱

All the expensive specification i.e. 63A max load, 30mA top tier sensitivity, 3phase supply and good brand like ABB/Hager using VI design (works regardless got voltage or not) will cost 290-300 bucks for RCD alone easily exclude installation.

At 300mA 🤦‍♀️, VD type (won't work if no voltage), non high end brand (Schneider and below) easily half the price but ZERO life protection. ☠☠☠☠☠☠ It only protect building for FIRE 🔥 protection. Not to mention, its illegal to use 300mA in residential...CHEAP mah! 😅

This post has been edited by ceo684: Mar 29 2022, 07:03 PM

Yes, lower mA trip current is safer.

Humans die at 50mA current.

Pick your poison between 30mA, 100mA, 300mA.
Two of them can and will ☠. Just a matter of whether ☠☠ or ☠☠☠☠☠☠

Holy cow. Lucky I asked. kknccb contractor.

Spent 10k to upgrade to 3 phase thinking can get better safety. Manatau...

So this EPS brand ok? Saw they use EPS brand in the whole DB box.

Going to tell the contractor to change this RCBO...Which brand should I tell him to change to?

Should I call other electrician to double check or audit their work? Scare kena electrocuted.

3phase and 10k reno should use ABB or Hager for the mains RCD 30mA (0.03A)
EPS boleh pakai lah..local brand.. but I personally prefer ABB. Safety item really you get what u pay for

⚠️ Also ensure you have individual 10mA (0.01A) per each water heater unit.

If MCB is EPS, can still mixed with Hager RCD?

So I just tell the electrician to change the 300mA to Hager/ABB RCD 30mA?

If I got 4 toilets with water heater, then have to use 4 individual 10mA RCD? Or just use 1 10mA RCD?

Suddenly feel like kena kencing by contractor... Damn sienzz...

If MCB is EPS, can still mixed with Hager RCD? Yes

So I just tell the electrician to change the 300mA to Hager/ABB RCD 30mA? Yes

If I got 4 toilets with water heater, then have to use 4 individual 10mA RCD? Yes 4WH = 4x 10mA RCD's is best. If DB no space issue, can use Schneider 25A 10mA RCBO

The best way to install RCCB for water heater is installing it nearby the water heater, if you don't mind aesthetic

my 14 years old house main db with 63A 100ma RCD and 40A 100ma, 3 WH with 20A MCB only (zero protection)



recently swapped with new db and upgrade to 63A 30ma RCD and 40A 30ma and 3 WH with 25A 10ma RCBO

Appreciate your reply.

The Hager/ABB RCD 30mA can support the whole house? Even with 3 phase wiring?
I only have 1 DB box for story terrace house. Contractor say 1 DB box enough liao.

Can, I'm using single (whole house) 30mA RCD w 3ph supply to type this

So complicated

So 1 number of 63A Hager 30mA RCB for whole house, replacing the EPS 300mA 63A.

And 1 25A Schenider 10mA RCB for water heater

hager 63A 30mA RCD for power socket and 40A 30mA RCD for lighting and fans, then 25A Schneider 10mA RCBO for water heater

no need lah, this is 2022
we are not in the business of selling RCDs
MS1979:2007 COP55 mentioned can put one single whole house RCD [at origin of installation]


the code in force is Electricity Regulations 1994
back then:
a. nobody use LED light. all use leaky fluorescent tube.
b. nobody use inverter at home for AC and fridge.
c. my Sony VCR also leak current, always kena zap from metal body. it came with 2 pin plug.
d. people use CRT TV

nowadays
appliances are made better with much lesser leakage current
meaning to say there's no actual need to use so many mains RCD's [this is in relation to some who propose one 30mA and one 100mA]
when one single whole house RCD 30mA can comply fully.
note its "maximum tolerance allowed" not "identical die-die must be exact"


----

as for your suggestion it is not wrong.. actually split load design is to have half the lights and half the sockets on each mains RCD (two mains RCDs), not split by lights vs sockets. Because again, 2022 everyone using much better made items with much lesser residual leakage current.

to expand on your suggestion, 3 phase supply CAN also be protected with 3x single phase RCDs.

split load pro: so in the case one RCD trips, you still have half the things running until user figure out what's wrong
split load con: cost of extra RCD

This post has been edited by ceo684: Mar 31 2022, 12:05 AM

Panduan_Pendawaian_Elektrik_ST_Edisi_Baru_2015


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 Panduan_Pendawaian_Elektrik_ST_Edisi_Baru_2015.pdf ( 7.24mb ) Number of downloads: 74

This is really interesting stuff, wished last time Kemahiran Hidup class got learnt this things.

Hi all, my current water heater is not connected to RCCB. I plan to install RCBO instead of RCCB due to limited space at my current DB box.

Question, since the neutral wire from double pole switch for water heater is connected directly to the neutral busbar in db box, how can I identify which is the neutral wire for it, so that I can divert it to the outgoing at the RCBO? Many thanks in advance for your reply.

By the process of elimination.
Obviously, it won't be the 1.5mm thin wires.
So out of the 2.5mm pile..
disconnect half and test continuity. (isolate the bunch u disconnected - make sure it doesnt contact elsewhere). if its not lighting up the double pole switch LED then u have isolated that "half" - its somewhere in that isolated pile.

Its not hard, but its annoying coz you don't know which is which at the neutral. But it is a necessary evil and salute you for installing a 10mA RCD/RCBO anyhow.

I saw some RCCBs listed as 'High Immunity'. Is this HI the same as anti nuisance trip feature or it's something different?

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.