I'm renovating my house and will change to 3 phase electric. Beside that, I would like to use smart switch in the future, so all the switch area has been pulled a neutral wire.
I want to ask whether my electric box is installed correctly and is it safe?
Because I saw the neutral wire all are connected together, but I do some research from online, it showing neutral return to own phase but the difference is that it uses MCCB, and mine is ELCB.
So i'm not sure if all the neutral connected like the image below, will have any cons?

My neutral wire image:



Whole box:



This is what I get from online:



Between, ONE Live wire can connect to how many LED light? I saw my switch area only have one Live wire, and uses to control seven 18W downlight, and one wall Fan, will it overload?

looks fine to me.


18W X 7 = 126W
126W + 100W (normally) = 226W.

Normally one point should be a able to support at least 1000W or more so you should be fine.

i emphasis on normally bcs i have seen contractors cut cost and use cheapo wires

This post has been edited by COOLPINK: Mar 3 2021, 02:54 PM

No issue if neutral come from other phase?

the return N to tenaga supply is 1 wire only .

i see your concern here.
its no issue but the ampacity needs to be taken into account if shared neutral.

did you appoint a qualified electrician for your house work?
if so you could ask him to explain to you what the electrical plans are for a piece of mind.

Linking all neutral together is ok since only using one three phase rcd.

As for the lighting wire it depends on the wire size and the connected mcb.
7 downlight and a fan would be about 200 watt or about 1 amp.

Assuming it is 1.5mmsq wire connected to a 6 amp mcb. It still has plenty of safety factor.

Assuming the load is balance accross the phases, the load on neutral would be zero.

But it is extremely important that the main neutral link to the supply is extremely well secured and tightened. Or else it might have unstable voltage ranging from 220 to 415 supplied to electrical equipment or you might hear a boom from the distribution box.

1. Better upload as attachment rather than use the upload images function (too low res to see)

2. Water Heater RCD (one each per WH unit) From the pic, no 10mA RCD for water heater was installed. This is statutory requirement. For old installation nvm but since you gonna redo, follow current standard.

Why 10mA RCD needed for water heater?
Because wet floor has very nice conductivity for fault current to flow through human = https://www.malaymail.com/news/malaysia/202...c-shock/1896447

ELCB is dinosaur technology
ELCB in WH cannot, will not, and certainly DID NOT protect against leakage for current flowing through human. It only protect L-PE leak (ie equipment protection only). L-N or L to other E (wet floor) leakage is not included in ELCB scope.

How much does this RCD (or RCBO) cost?
RCD ABB (Italy) or Hager (France) ~168 (online)
RCBO Schneider (PRC) ~100-105 (online)
other china brand also around 70 bucks but this is one thing not to skimp on.. treat it as a one off life insurance.. without yearly renewal. Maybe change once per 20-30 years.


It only takes 0.05A of 230V to kill a person.


It is very easy for an electrician to hook up a 10mA RCD per water heater circuit. Just need to identify the dedicated N for that circuit and connect to RCD 10mA. RCD 10mA line side L feed from 20A (C20) MCB load side; RCD line side N connect to common neutral. It is not rocket science. But it will definitely protect you so you can buy me a coffee.

3. All the N is common neutral when it return to TNB so basically it is correct. Common neutral and common PE (Earth).
Individual circuit (dedicated neutral) is required for special case like 10mA water heater circuit.

4.ELCB is old dino tech, you mean RCD/RCCB for mains protection right?
Only one mains (whole house) 30mA RCD needed to cover the whole house.

Use 30mA (0.03A) as whole house RCD (aka RCCD/RCCB) will give you best life protection (in general) against any fault current - be it 13A socket or light circuit. And it serves as a useful secondary line of defense even if the 10mA failed to trip on time (for WH RCD).

Note:
Anything else (100mA / 0.1A) or (300mA/0.3A) gives fire protection for building protection only. These do NOT protect human life.
Coz if there is a fault, the human dieded 2x or 6x over.

5. As for the 18W lamps.. you will need 100 pcs of them to be equivalent to a single electric kettle. One ceiling fan only takes about 85W. All in all they are low loads.
I doubt you will exceed a total of 6A (1380W) even if whole house LED and ceiling fans are turned on simultaneously.

The ones to look out for are the big loads such as water heaters (3000W typical storage heater) or (3300W-3800W typical instant heater); kettles ~1800W;; rice cooker slow cooker; oven be it microwave or conventional; electric stove/hob/induction cooker/air fryer, basically in short heavy heating appliances do not do looping shortcut but run a dedicated line to DB box with proper MS2113 cables (mega kabel, caramay, fajar cable).

6. Choice of 3 units of single phase (2P RCDs) per red/yellow/blue phase or 1 single unit of a three phase (4P RCD).
Both are not wrong, the 3x of 2P RCD is more for "business continuity" in case red phase has fault, you can still operate things on the yellow and blue uninterrupted.
Whereas in the case of using 1x of 4P RCD, any one phase has fault detected, entire house goes dark until the fault situation is rectified.
Cost wise, one 4P RCD is still cheaper relatively as compared to three units of 2P RCDs.

This post has been edited by ceo684: Mar 4 2021, 12:38 AM

Yes, this is also important as phase-neutral is 230V
But phase to phase produces 415V fireworks show.

Neutral looks ok
Your rcd is not

Since you reno, do it right

100ma for main or lamp
30ma for socket
10ma for water heater
Get reputable brand pls.

Why buy 2 piece of mains RCD 100mA and 30mA when the requirement is "maximum of 100mA tolerance" - i.e. NOT "equal to 100mA" or "not less than 100mA tolerance"?

A single 30mA for whole house is cheaper TCO and provide better life protection whilst still fully compliant to the regulation of "maximum of 100mA tolerance".

This post has been edited by ceo684: Mar 4 2021, 12:48 AM

Yes is correct
In practice is better to use 3 units of 30ma single phase
So when trip won't bring down the whole house power.

It's not only about compliance but rather safety and convinience

Ts if have money pls add spd too

Yeah the ideal is to use 3x 2P 30mA but only two concerns:
1. Cost-wise it is also OK to use 1x 4P 30mA if budget constraint cannot stretch. Protection wise, TS, is the same as long as all are 30mA.
-- The only diff is any fault will trip whole house, rather than just that one phase.

2. Physical limitation of DB box space. It looks kinda full at the moment.
-- 1x 4P use 4 module, vs 3x 2P use 6 module space.

3. 3-phase (4P SPD) for lightning protection
individual module replaceable type
-- CHNT (china brand) 40kA 4P ~423
-- ABB OVR-T2-3N-40-275PQS SURGE PROTECTIVE DEVICE [2CTB803973R1100] 40kA 4P ~480
-- SCHNEIDER A9L40600 iPRD40 MODULAR SURGE ARRESTER A9L40600 ~379

monobloc (use and throw as whole unit)
-- Hager SPD SPM440E 40KA 4P ~502
-- Schneider SPD A9L15688 40KA 4P ~490

useless toys:
those 30 dollar china SPD

This post has been edited by ceo684: Mar 4 2021, 01:10 AM

Thanks man.
1. What is the "MCB C20 WH"? is it different type of other MCB?
2. if I have 4 header, which mean I will need FOUR 10mA RCD?
3. The purpose of 10mA RCD is to trip when the heater leaking to our body? my current installation if leaking it won't trip?
4. In short, I only need to have 10mA RCD in between the MCB and Header individually? Any other wiring need to be change/improve?
5. between I'm quite confusing are ELCB & RCCB the same? can you correct me if the naming in the image below wrong?
6. Appreciate if you can share the image of "MCB C20 WH" and 10mA RCD



besides that, there are 2 type of MCB in the box, C10 and C20, click the link to see high res image:
image 1
image 2
image 3


This post has been edited by hendry91: Mar 4 2021, 10:40 AM

This post has been edited by slimey: Mar 4 2021, 11:54 AM

Sis actually.

1. What is the "MCB C20 WH"? is it different type of other MCB?
Standard C20 MCB.
WH denotes the one for WH circuit.

2. if I have 4 header, which mean I will need FOUR 10mA RCD?
Yes correct. WH 10mA RCD is per unit of WH. Each WH should be on its own dedicated circuit as one WH enough to use 15-17A nominal (WH is heavy appliance). Your 2.5mm cable only support 21A. And the 10mA RCD, only come (from branded mfg) up to 25A max current. In short, the standard cable sizing, the RCD current capacity (max 25A) all only suited for single unit WH as it is sensitive device (0.01A /10mA).
Whilst there are champions from china making 10mA RCD that can handle 40A I also dare not use.

3. The purpose of 10mA RCD is to trip when the heater leaking to our body? my current installation if leaking it won't trip?
Your current installation only trips at 300mA - by then, the human dieded 6 times over.
As the mains is 300mA, it allow 300mA leakage before it trip.
A human RIP at 50mA.


4. In short, I only need to have 10mA RCD in between the MCB and Header individually? Any other wiring need to be change/improve?
Yes, correct.
RCD is comparing input and output current difference. Input and output must = equal the same +/- RCD tolerance of say 10mA (0.01A).

Meaning, if WH input is 16A on L, at least 15.99A must return on WH output (N) else it has deemed to be lost somewhere.

Lost somewhere mean could be leaking through human.
So when the return not enough (<15.99) say only 11A return. The 4.99A cannot be lost, it mean it leak. As 4.99A far exceed the 0.01A allowed by 10mA RCD it will immediately trip.

MCB only consider single wire (L) amount of current passing through (short circuit prevention).
For a C20, meaning the speed limit is 20A.
Slight overload at 23A will trip the SLOW thermal overload after say 20 min.
Major overload at 100A will immediately trip the magnetic overload.

5. between I'm quite confusing are ELCB & RCCB the same? can you correct me if the naming in the image below wrong?
The difference is how and where they measure.
ELCB only detect earth current rise >0 leak (L to PE) leak on that appliance's earth. If it leak via anywhere else (L-N, or L-other PE eg wet floor, L-human) it will not bother. Hence in short I just say it protect that appliance only.

RCD because it constantly compare L input =N output + allowed tolerance (like 10.00A in on L, >9.99A must return as allowed tolerance is 0.01A for normal operation things like wire resistance that do NOT constitute a fault condition). It does not care where it leak through, RCD always compare in and out current so if it leak through any method (L-N, L-PE, L-other PE, L-human) it always trip.

Note: There is something called RCBO which do both function of MCB+RCD in one.


6. Appreciate if you can share the image of "MCB C20 WH" and 10mA RCD
MCB C20 is any usual C20 (20A MCB). WH is just designation for the WH circuit.

10mA RCD (must be used in conjunction together with C20 MCB) ie. add this along with MCB C20
ABB= https://www.lazada.com.my/products/abb-f202...i2IABn&search=1
Hager= https://www.lazada.com.my/products/hager-cc...l5n2dU&search=1
Schneider = https://www.lazada.com.my/products/schneide...8t5PsK&search=1

10mA RCBO = RCD+MCB in one package pao kah liao 2 function in one
Schneider RCBO https://www.lazada.com.my/products/schneide...PVCaV4&search=1
The drawback is, officially, their MCB is a C25 equivalent so you need to use with 4mm cable. As 2.5mm cable only good up to 21A rating.


First one from left is MCB 3P (3 pole) C63 (63A)
Second one is 4P RCD but this is 300mA. Only used in commercial/industrial where they use heavy motors. Not safe for residential and its against regulation, as the human has dieded 6x before this trips. (RCD/RCCB/RCCD = same function with diff name like zebra crossing=pedestrian crossing)
Third one is MCB 1P C10 (10A)

You will then ask, why do people still put the 300mA in residential?
Just to save the few bucks for more profit/lower tender cost

This post has been edited by ceo684: Mar 4 2021, 01:59 PM

wah lau eh you guys can see the wordings on all the CB from the first pic.

i cant see shit man.

Thanks slimey.
Ya, I feel you. I don't like their cincai style, I hope they organize the color of the cables according to the regulations, but it doesn't seem to be.
Kampung area all kampung style, maybe they don't even have a cert, but worked for a long time and followed the old method.

When I request the technician to pull the neutral cable to each switch area for smart switch, but he totally can't get it and need my long explanation.
and also ask him to hack the wall to put an empty pipe for Unifi fiber, but he told me can pull Cat cable, it's the same. I know he was outdated.

So I must do some research, and study by myself to make sure everything is correct.

Ops, Thanks Sis. haha

if 300mA RCD is for commercial/industrial, then what should be used for residential? RCD with lower mA?

Let's say la, I take a fork cucuk the 13A socket and kena shock, my MCB / RCD which one will trip and what's the cause(theory) to make it trip?

This post has been edited by hendry91: Mar 4 2021, 03:06 PM

Ideally all 13 amp socket is protected by 30ma trip characteristic rcd/rcbo.

And as for the cucuk 13a socket. It depends on how you cucuk lo.
If you cucuk live only and you kena shock. It depends on how grounded are you lo. Normally it will be a ouchie only and you quickly retract your hand lo. If rcd is rated at 300ma or 100ma it will not trip lo. If you are very grounded ..... let’s say you touch a metal ground of an appliance and you also touch live, it will be extreme ouchie or you die.

If you cucuk live only with one metal, cucuk neutral with another metal, and you hold the metal one in each hand, you will die regardless of rcd or mcb. Because to the circuit, you act like an appliance.

If you cucuk with a folk with both the neutral and live going in at the same time, the mcb will trip lo.

This post has been edited by slimey: Mar 4 2021, 03:16 PM