This is untrue. ST requires 10ma RCCB for all type of water heater. Plug and socket for water heater inside toilet is banned. I know why it's banned.


Latest Guideline for water heater

i just checked my single phase db beside the lever have 63a 100mA rccd, so it is suggested to replace with 63a 30mA 2P? my house quite old already 20+ years

ABB https://shopee.com.my/ABB-RCCB-ELCB-FH202-A...93-457ea2c660fb
Hager https://shopee.com.my/HAGER-CD263B-63AMP-2-...e1-9498152d9ef1

This post has been edited by xkaizoku: Aug 3 2023, 01:46 PM

This ABB model I think without anti-nuisance tripping function. Hager model stated with anti-nuisance tripping function, fyi.

nope, ABB does have


https://library.e.abb.com/public/7115a45a1e...421002B0201.pdf

Ya I know this model got. What I meant was the one ABB model FH202 quoted by him earlier in the shopee link.

which ABB model have?

https://library.e.abb.com/public/7115a45a1e...421002B0201.pdf

This AP range but not sure is commonly available online in Malaysia or not.

Actually ABB FH202 AC-63/0.03 does has anti nuisance tripping. You can search using its SKU at ABB website where it does list 250A max surge current. AP-R range is their high immunity model and usually hard to find ready stock. If you have excessive tripping during lightning that not even close by, it is usually due leakage/short from neutral to earth that high resistance enough preventing it from tripping the RCCB on normal days. Only the lowest end consumer RCCB (for 30ma/100ma) don't have anti nuisance tripping.

This post has been edited by jio: Aug 30 2023, 09:34 PM

Is this DB ok? Need some advice before proceeding. Thanks in advance!




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Ok except the last one use 40A 0.03A


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Ok.Will get it replaced. Thanks a lot

I believe you will have unnecessary tripping faults. You have made a common Neutral busbar for both the top RCCB (Marked "40A 30mA" - Let's call this RCCB1) and the bottom RCCB (Marked "63A 100mA or 40A 30mA" - Let's call this RCCB2)

This may happen : Current flows through RCCB1 live > MCB 16A > socket in room > appliance > Neutral wire back to DB > Neutral busbar > RCCB2 Neutral.
Your RCCBs will trip. You have to split the Neutral busbar for RCCB1 and RCCB2.

The WH Neutrals must be connected to the RCCB2 Neutral busbar, as the current to the WH originated from RCCB2.

Also, physically, when I am making the connections, I would connect the 10 mm² wires together. This is for the WH Live. In the drawing it is connected through the Live busbar at each end. Potentially the Live busbar will heat up.

This post has been edited by stormer.lyn: Oct 3 2023, 09:08 PM

Oh no, The DB box only has 1 neutral busbar. Need to change DB box or can add another neutral busbar?

For the WH live you mean replace the busbar to 10mm wire instead?

Thanks ya

May i know why you say so?Do you mean to have 2 separate Neutral busbar?
Eventually all the Neutral will be connect back to incoming(main) Neutral right?

This post has been edited by lankorn: Oct 5 2023, 01:07 AM

Actually on second thought. Why not just use a single 63 0.03 RCD since it’s on single phase. There is no need to split DB.

It’s because the neutral group of circuits on RCCB A should not be mixed with neutral group of circuits on RCCB B before passing the “checkpoint”.

I cannot understand .Can you draw?

This post has been edited by lankorn: Oct 5 2023, 01:30 AM

Mixing your neutrals BEFORE the RCD "checkpoint" has different implications.

U know how shops like genki sushi and sushi king charge for per-plate kaiten belt sushi?
RCD operates like u eat, u pay for your plate tower.
Now let's say I eat, I don't know you, but I put my plates into your table.

This post has been edited by ceo684: Oct 5 2023, 01:52 AM


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Done changed the RCCB & DB box to the one with double neutral bars.

Should be good to go right? Waiting for the wireman to fix on weekend.


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Yes, this diagram looks good. What I meant about the water heater live wire is in the picture below.



This is the physical connection of the wires. This way the Current to the WH doesn't go through the busbar, but goes wire-to-wire. If you look at a busbar, the bar is rated for 120A (example) but the tines are rated for the Current to an MCB only. They way wiremen stuff the incoming wire into the MCB and get it to distribute is dangerous in my opinion.

Sorry, a bit busy to get on LYN. In the marine line, many ships right now. But I'll try to get back to you asap if you have any further questions.

I see. True also. Possible to slot 2 10mm cables & busbar tines into the same mcb . I mean does it fit?
Thanks for everyones input on this. Really appreciate it.