any possible reason that the fuse will be malfunctioned?
when i mentioned malfunction, means the smart meter digital reading also no display..
so the quick solution was to replace the fuse, then it works again..

could be overloaded? why say so, coz what i noticed was, i was using below at same time:
- dryer
- vacuuming floor/dust
- ac 2.5hp
- ac 1.0hp x2unit
- other basic devices no need to mention: tv, fridge, fan, etcs..

and out of sudden tnb meter no display.. neighbors were fine


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yes ..overload . blow the fuse. or one of your device faulty .

temp ..you can connect a wire/ thick at the fuse connector , to get power
and go to the shops to buy a fuse if you want fast .
if not call TNB.


This post has been edited by Momo33: Feb 14 2022, 11:25 AM

never happen to me
i got 1x2hp AC, 3x 1HP AC = ON

kitchen rice cooker + oven = ON
water heater + ON

all on at the same time

maybe replace with higher cap fuse will help?

As you can see the switch in your DB is 63A which means the single phase current is limited to 63A for a house with single phase. The fuse supplied for my house was 35A (if not mistaken, I forgotten already). Some house the contractor gave 60A fuse. Mine cheating I guessed

One day when I was back home from work my house has no power. Luckily there was still one electrical shop that was still opened at almost 7pm that day. So, I bought a replacement fuse rated at 63A (or can use 60A). The TNB website said an online application is good for 60kW application or 100A.

Don't simply use any wire and assume same wire thickness will carry max power the same as the blown fuse as permanent replacement. The wire rating is not by size or diameter only but also the material.

your single phase , MAX is 63 A fuse.

my quick A usage check on your usage , you are not using more than 63A ,
so man not sure why it blew the fuse or its just too old fuse that it blew out.

to be safe if you use the dryer , off 1 or 2 other . like vaccum cleaner .


what is the rating of your ELCB/RCCD ?

do you have a main fuse on your DB ..what the rating ?




This post has been edited by Momo33: Feb 14 2022, 12:53 PM

no you cannot simply replace as you like as others mentioned.
fuse is a safety device and the max rating must be strictly observed.

the proper solution should be tracing the devices/wiring that is causing the burn out instead.

the photo on 1st post was just a sample from googleimage.. lol..
i think my smart meter is 100A, it clearly written there as attached.
so should be safe to change to 100A fuse?
if yes, well.. tnb should also change the fuse when they change new smart meter..


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The meter is 100A because that probably the limit TNB set for a single phase line. Most important is to look at your circuit breaker and the main switch in distributor box (DB). I bt the switch and the main circuit breaker is 63A rated. So, stick to the rating.

Some old house use 32A fuse, based on your description you exceeded 32A. Need to upgrade to 60A but check with TNB first.

If not mistaken, the TNB portion is until the meter only. The fuse than internal cabling inside the house are the responsibility of the contractor. The fuse is supplied by the contractor, not the TNB.

The house was doing fine with old fuse. Same like mine. It was just happened that the fuse gave up one day. Probably deteriorate over time and just failed, I don't know. Not everything perfect So, it is not due to overload sometimes.

The supply goes to the fuse first, then meter or vice versa ?

Fuse > Meter > Main Switch > Main Circuit Breaker (ELCB, RCCB or GFCI) > MCB (Mini Circuit Breaker) > Lightings and appliances

Additional reading
http://www.axanaga.com/v2/download/Suruhan...alBuildings.pdf

This post has been edited by Zot: Feb 14 2022, 01:01 PM

Isnt then the fuse is tnb reponsibility ?

After changing the fuse, try to clamp & record ur voltage reading. Better monitor ur usage

But if u not sure, asked electrician to do it

no reading at the mcb

Your incoming MCB is located at the Distribution Box(DB).Open up the DB box, see what is the main incoming MCB rating.

The more accurate way, get the meter clamp, clamp the single phase cable, see what is the running ampere & compare it against the rating of fuse when you are operating all the devices together. If the ampere reading at the clamp meter is close to the fuse rating, it is obvious overloaded.

If overloaded, the only solution will be upgrading your incoming to the 3 phase. By upgrading, the TNB will upgrade the incoming cable size, the metering panel from single phase to 3 phases, the fuse will be upgraded. On the owner side, your DB need to be upgraded to 3 phase also.

so it is 35a, or 63a?


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looks like 32A.

32A SPN. This device was not tripping, get the electrician to check the functionality also.

With 32A SPN, max you can use concurrently should be limited to around 6kW only. It was overloaded.

This is how to read them

https://www.electricaltechnology.org/2015/0...ata-rating.html

The number you see is the reading. The C in front like C20 is the type (characteristic behavior of the MCB), 20 means 20A. The 6A is for lighting and fans. The 20 one is for 3-pin socket. You can see more on how the recommended rating for different purpose in the Guideline link I provided.

So mcb uses 32a but fuse 35a?

What you mean? Illogical to put 60A fuse on the 32A main CB, right? Your main CB is only 32A?

The CM rating is the same as fuse, normally.

This is the main switch?
Pls take clear pic of whole DB box and the two largest blocks in there for better commentary.

And use the clamp meter to check the outgoing current.

attached, thanks all!


Attached thumbnail(s)

Your MCB is at third row next to RCCB and it is 63A.

Is it single storey house with one DB?

Did the power cut happen when you turn on any house appliance?

This post has been edited by juzmafia: Feb 15 2022, 02:39 PM

thanks for reply..
it is single storey built since 2015, while stayed since 2017..
only one db box here..
i only suspected due to turned on heavy load appliances at same time, as mentioned:
- dryer
- vacuuming floor/dust
- ac 2.5hp
- ac 1.0hp x2unit

Even if it is turn on at the same the MCB should trip, not the TNB fuse.

Did you check the old TNB fuse amp rating and is the new TNB fuse amp is 63A?

tbh.. i ain't sure the existing and replaced fuse is how many A
but from the pic.. confirmed it is 63A?
maybe i should buy one for standby.. how much would it cost?

Err..I thought you bought yourself..😅

Fuse amp rating is very² important, too high or too low is not good.
It protects both circuit and equipment.

Better check properly or better ask electrician to check overall.
If the old TNB fuse amp is 63A then better replace the MCB as well.

This post has been edited by juzmafia: Feb 15 2022, 03:35 PM

hmm but as u mentioned the mcb is already 63a?
then i jz need to confirm the fuse is 63a too, right?

Ya but if your old TNB fuse is 63A then during overload the MCB should trip earlier because it is the first defence for your house circuit. If MCB fail then the tnb fuse will trip(blown)

That's why if your old TNB fuse is using 63A(which i think it was) then MCB has failed to protect so better replace it. Better be safe than sorry.

..or another reason for the fuse blown is due to short-circuits happen between the TNB fuse/meter and Main DB.
Can refer this thread: https://forum.lowyat.net/topic/3973648/all

This post has been edited by juzmafia: Feb 15 2022, 05:29 PM

Ok la new place so we will rule out colonial era wiring and PPR flat which may be on 40 supply.
Most new places should be 63A supply.

Original DB came with 63A rated big blocks so it reaffirms circumstantial evidence above. If you have 40A big blocks that would be cause for concern. 63A big block should be ok as, costing wise they cost more than 40A big block equivalents and nobody would overspec..unless really clearance sale.

The TNB cutout fuse is quite slow.. If the MCBs dont trip but the fuse trip it might be a slow overload.. so happen all devices kick on at same instant. C curve MCB Imax is 5x to 10x rated.

I would like to dig whats on the 32A 3rd party additional circuit MCB.
Is that for water heater? The DB box is technically cost cutting and fails code "Electricity Regulations 1994" as NO 30mA RCD, NO 10mA RCD for water heater.

This post has been edited by ceo684: Feb 15 2022, 08:29 PM

I am having sound and a little bit of spark coming out of the Fuse Box also. Can I get my electrician to change that Fuse box only? the TNB meter seems to be fine

Before meter main fuse? that is TNB portion. call TNB to replace.

if its the DB box one AFTER the meter (homeowner part) then u replace.

This is a std fuse 63A perphase from TNB. You cannot replace it with higher Amp.

To solve it, apply for 3 phase. Each phase 63A x 3.