I'm very short only. That's why have to look up on you

Actually, I thought as long as I add an RCCB, I need to identify the neutral wire no?

My original setup based on my friend's advice :
Live busbar --- wire --- RCCB Live Top --- RCCB Live Bottom --- MCB Bottom --- MCB Top --- Water Heater Live
Water Heater Neutral --- RCCB Neutral Bottom --- RCCB Neutral Top --- Neutral bar

New setup :
Live busbar --- wire --- MCB bottom --- MCB Top --- RCCB Live Top --- RCCB Live Bottom --- Water Heater Live
Water Heater Neutral --- RCCB Neutral Bottom --- RCCB Neutral Top --- Neutral bar

Yes I managed to identify the neutral wire. Small apartment, and developer was generous enough to use a 4mm. Only 2 of these.


Bro, did you misunderstand my posts? Or you see something wrong with my setup having MCB before RCCB?

Thanks for your responses.

I might have actually ... when you typed " I'm protecting the RCCB because it's much more expensive." ..

My mistake..

Your setup is a standard arrangement i.e. The RCCB (or RCD) doing the protection of life, while the MCB protection for the property (cable, RCD & load)..

It's good..

thanks bro Richard

Back to the original topic.

Anyone here use MCB Type B at home? Seems like everyone is using Type C, but of course, most were probably installed by developers. Forgotten to find out if Pasar Road is selling Type B. The last time I bought, I didn't know the existence of Types B C D, they just gave me a Type C.

I only experience seeing type C in the market..

Physically the difference is nominal (I.e. in name only), as it deals with the breaking capacity of the breaker.. thus the physical characteristics of the spring.. you would need a department like SIRIM to be able to tell the difference..

You and me, we take and accept what is available..

hmmmm that's where my concern is. Or probably it's unwarranted.

Type C will only trip at 5x its rated current. If my understanding is correct, there'll be no trips below 5x. On a 20A Type C MCB, it means that 99.9999A can flow through the cable without it tripping. If it heats up the cables long enough, fire or short circuit.

Of course, knowledgeable people know not to overload any particular circuit, but we can't stop anyone from doing so.

This was the reason why my friend said there's no point protecting the RCCB with an MCB. I guess there's no harm trying though

I don't think I've much choice. Seems like it's our norm in this country to compromise safety for convenience. When I goto shops for 10mA-30mA RCCB, they'll always tell me "don't buy this, always trip". I guess the same applies to MCB, so no Type B for the wicked.

Some of the rare or hard to find items, i usually pay a bit more and buy at element14, The B curved should be available there

http://my.element14.com/abb/s201mb16/mcb-1...urve/dp/1775068

Thanks bro weikee.

Yes, I found it there and my friend is using element14 exactly as you - for rare items. These are made in Europe too Costs 8x more though.

http://my.rs-online.com/web/c/automation-c...archTerm=S201b2 seems cheaper than element14. I don't know who will do the customs clearance and not sure if SIRIM approval is needed.

Edit : Ok, my friend say all the clearance will be handled by element14.

This post has been edited by beLIEve: May 11 2017, 12:13 PM

Correction..

On a 20A Type C MCB, Once there is an overload current meaning more than 20A the breaker will trip .. There's a coil within which pulls in a metal piece (an electromagnet) which trips out the breaker..

Type B, C and D only refers to the inrush current .. produced by inductive lighting and motors.. The 5x is a transient (momentary or short time only) current during the start to enable starting torque(of a motor) or to jump a spark (of lights)..

Once the motor is running or the lamp is lit, the current goes back to rated normal..

A continuous flow of overload current (beyond 20A) will heat up a secondary part of the breaker (a bimetal strip)..

Your friend is misinformed .. A MCB protects against an overload (both magnetic and thermal type), a RCD protects against leakage current (below the rated) but will kill a person..

You need both devices in your DB, one to protect property, the other to protect life.. It is a mandatory (MUST HAVE) requirement..

For the secondary RCD at the water heater I believe it is only recommended not yet enforced by our Suruhanjaya Tenaga..

If you read the news then you know that people have died due to faulty electric water heaters .. 50mA AC Voltage over 5 secs will kill a fully grown 60kG human male..

You can google, read it up or ask any medically trained person.. The symptom is similar to a heart attack with burns at the contact areas..

Edit*

If the device keeps tripping then there is a leakage current, dirty equipment in a high humidity environment is the usual cause...

The dust settles on the live or Neutral wire and when wet will leak to a conductive cover tripping out the RCD..

You need to clean the electrical devices.. Wet dust can conduct electricity..

Edit**

Correction For the secondary 10mA trip RCD at the water heater.. It is a mandatory requirement by Suruhanjaya Tenaga..

This post has been edited by Richard: May 20 2017, 08:43 AM

Some items selling in element14 is not expensive. I got the velcro tape same price as Ace, and they have stock. 7AH Battery RM 63+ and i can at least sure the quality are better. Raspberry Pi + Camera much cheaper than outside price.

Thanks bro Richard. You just answered my question! I did some further research based on your answer and found out that it's available on Wikipedia. All other sites just explain the magnetic trigger, which is 5x-10x the rating for our Type C. That explains the line curve to the left of the 5x-10x "rectangle".

This also explained what I observed with my neighbor's MCB. When I first reset the MCB that goes to the faulty line, it took a few seconds to trip. Subsequent resets are almost instant. So it's the thermal effect - it hadn't cool down. I disconnected the faulty link which is last in the loop and no more trips. There was already a partially (say, 10%) melted plug when he got back the house, so I think it's beyond dirt. Not within my skill to fix that

For the RCD, yes, I've searched and read before, just for reading pleasure. I tumpang my friend to buy the 10mA and 30mA RCCBs when he bought his before all the readings. So my house is fully secured, at least, to what is within my knowledge. I'm still using a stack of Type 2 MCBs from the developers though, need to research how much they differ with Type C. I briefly read the other day, Type 2 is old standard.

My friend got everything right minus the thermal tripping part. He was the one who told me about the 10mA and 30mA RCCB. So yes, it's not enforced yet. By the time it gets enforced, there'll be a shortage in supplies

And yes, ventricular fibrillation.


Thanks for the tips. Long story short, my old 100mA used to trip on lightnings while neighbors' houses aren't. Now the new Hager 30mA (I use as main RCCB) survived many lightnings. It tripped once without lightning. At that time, only the fridge and fan is running (2 different circuits). So I think I'll have to clean some wires. I noticed many of my wires have paints on them. Contractors must've painted before they install the sockets. We're the second owner, apartment is 20 years old now.

bro weikee :
Ahhhh ok, thanks for the info. I just briefly browsed that site. Friend told me there are wires better than Mega. So I just searched for the wires, for the sake of knowing, and the MCBs. Both are much more expensive than Pasar Road. I'll check out element14 next time.

This post has been edited by beLIEve: May 12 2017, 02:41 AM

1 aircond draw 3.91 Amp, and we know 2.5mm cable can safely carry current up to 15Amp, so can i install 2 aircond using same cable?

Hi guys, have some questions due to disagreement with my electrician:

1) I asked to put 10mA 63A RCD for water heater + electric water closet + 2 power socket but he said it's better to do 1-to-1, meaning 1 RCD for 1 water heater instead, which does not make sense to me. Is 10mA too sensitive to be practical for what i am planning to use for? If not, i am planning to use only single 10mA RCD for 2 bathrooms lol.

2) He asked me to only use 1 RCD for all the lighting, fans and power sockets for the whole second floor, which i disagree with because it would mean total blackout when it trips.

3) I have asked for 30mA RCD for the lighting, fans and power sockets but he said to use 100mA RCD, which i again disagree with as anything over 30mA would be meaningless as it would greatly increase the fatality rate.

Having said that, i am concerned with nuisance tripping so would like to ask if there is anyone who changed 30mA for the house and 10mA for the water heater and experienced constant nuisance tripping?

4) Is it wise to use 30mA RCD for aircon? Or should i use 100mA or higher? Heard inverter aircon often causes nuisance tripping. But seems like no point when we go over 30mA.

Thanks!

1. your electrition is right.
2. that's up to you.
3. if you use 30 you will need more RCD than 2.
don't worry about nuisance tripping for water heater. for house you can get those with high immunity and protected by SPD.
4. same as 3.

technically yes.
also need to take into effect the distance of wires of course.

No. An Aircon compressor motor starts/stops multiple times acting on thermostat sensor

The starting amps will be 6x or higher and will burn out the mcb or connectors contacts. There will be arc damages initially slowly continuosly damaging the contacts and burn.

Any 4 Ampere Aircon compressor motor must have a dedicated circuit protected by a 20A mcb.

Only a single 1hp Aircon to one circuit. No more.

Dear sifus, is it weird that both Hager and Schneider do not have RCCB type A for 10mA or even 10mA RCBO with 20A or 25A rating?

Reason being is that some water heaters come with pump (mine does), so naturally the RCCB has to be type A (protects against pulsating DC current) instead of type AC isn't it?

And then there's the issue of RCBO being 16A, which barely exceeds the max wattage of some water heater. I know water heater does not usually run at full load but i am not willing to buy one to test if it will trip and end up not being able to use it.

Maxguard does produce type A for 10mA RCCB and 10mA 20A for RCBO but mixing with Hager MCB is a no no for me. Plus Hager has better build with better anti-nuisance features.

Also what SPD do you guys recommend? Type 2 that is installed after the main switch? Mine is a single phase DB. For Hager, there is this medium protection, fine protection, with reserve, without reserve and monobloc series, don't even know how to decide lol.

Installing SPD to reduce nuisance tripping during lightning as i will be using majority 30mA for sockets/lighting.

Lastly, is isolator needed and how does one arrange the DB sequence? And should RCCB be installed first before MCB or vice versa? Sockets>RCCB>MCB?

Thanks in advance.

This post has been edited by Cyberbullies: Jul 9 2018, 01:02 AM

Hello, I have read through few threads including this thread, I have some questions on RCCB for water heater. My house is using 3-phase power, and currently I have 2x 4-pole RCCB (100mA & 30mA) installed in my DB. Let's say I want to install additional 10mA RCCB for each water heater that I have, what type of RCCB to be used? 2-pole? How will be the wiring diagram looks nice? Appreciate your kind advise, TIA.

Your water heater runs on single phase right? Then 2 pole it is.

You need to find out which mcb is for the heater currently, and which neutral wire it is using if you plan to install it at the distribution box.

If too much hassle doing that, just install a 4 way distribution box next to the water heater switch with a single rcd, 20amp, 10ma tripping value. Wiring diagram is on the rcd.

Thank you for your slimey prompt response. I understand based on what you explained just now. Could you also enlighten me on questions below?

1) If I have extra space in DB and I choose to install the RCD at DB, will it be less effective compared to RCD nearer to water heater?
2) If I have to install at nearer to water heater, the RCD should be installed before the 20A switch as per sequence below?
(Main RCD (30Amp) - Water Heater MCB- RCD(10Amp)-20A Switch-Water Heater Power Inlet)
3) I found Hager 2 Pole RCD only has 16A and 25A rating with 10mA tripping value, which one should I get for my 20A water heater? (See attached photo)

Cheers!

This post has been edited by FrankieSiow: Oct 17 2018, 10:57 AM


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