Hi all,

Lately my house always suffer power trip randomly; e.g. not because of lightning or switch on appliance. Example; this morning around 4am power trip again.

MCB/ELCB did not trip; but the outside fuse near TNB meter blown. Always happened this way. Usually I replaced this fuse; but it will randomly happened again.

Any idea why it trip this way? And is it normal if I switch off MCB but TNB meter still show movement (very slow)?

have u report to TNB everytime the fuse blown? normally incoming problem before meter is under TNB responsibility, ask them to solve it.

outside meter fuse rating is 60ampere for single phase. basically fuse will blown when current overload.

Current overload from outside or inside?

Last time already called TNB, but they asked me to get a technician because probably due to faulty appliance or bad wiring inside the house. But after it happened again this morning; I'm not sure it originated from the house.

This morning, I off MCB; and right when I insert the new fuse it blows.

when you say you off MCB, is it the :

(A)


or

(B)

Both. In fact I switch all those in the MCB box.

i never had a problem with external fuse blown,
but i encountered a problem last month regarding my RCCB (the one in picture B).

power trip due to wallsocket faulty, but all MCB, RCCB, ELCB not tripped.
was puzzled at first, but when i tried turning ON/OFF the MCB & RCCB, the power is back on again.

it happened again afterwards, during a thunderstorm (and lightning),
no power due to lightning strike, but all MCB (picture A), RCCB & ELCB not tripped.

did some checking, and i assumed that my RCCB is faulty: there was no power in the house,
but the RCCB switch is in its 'ON" position (internal mechanism i guess).

changed my RCCB and it solved my problem, so far.

do you check your RCCB regularly (press the 'TEST' button to see if it can trip)?

No I didn't check the TEST button, will try it after I put back the fuse.

faulty earth cable maybe ?
or maybe the fusebox got cable short circuit ?

outside fuse cant blow unless the current masuk ur house...
but since u off all the fuse, still can blow , maybe its time to check back all then wiring between main fuse to your fuse box...

inb4, i main hentam pull out and plug in main fuse near meter when fixing my new house, never experience it getting blown...

if it works (the RCCB can trip using TEST button), then RCCB might not be at fault.
if it doesn't work, then why not try changing your RCCB first, and observe if the external fuse still blow afterwards.

like what MadhavanR mentioned, i also had the experience that normally the external fuse
can just cabut/replace to do anything to your main fuse box.. seldom that we'd have it getting blown (multiple times some more).

Which fuse? the one beside the meter?

- Your's is 3 phase or single phase
- What is usually turned on? like the incident this morning?

Forgot to add, I have already replaced everything in the MCB box after it happened the second time.

I think its single phase. Nothing unusual switched on.

since you've changed everything in the mains box,
then most likely there's something wrong with your house wiring
or probably the cable in-between the main lines - connected to your mains box.

is it a new house? are you the first owner/occupant?

If I am not mistaken, the fuse beside the meter is slow blow fuse (if its the one beside the meter), it take hell lots of current or high spark of voltage to blow that fused (shorting is one of the method). Or long use of overloading to blow that fused (Long as in > few second).

<Assuming your internal wiring are working> your's situation, the outside fuse blow at random time and internal fused box not trip, and internal Main switch (also fused protected) not blow / trip. Could happen if somethings / animal move a loose wire in between the meter and fused box inside.

Yeah I think so too. Already discussed with electrician to install a new wire between meter and MCB.

Did you off all the MCB before insert the fuse?

What you can do is isolated the problem to find out where it happen.

Before insert the fuse again, off all the MCB. off the rccb and take out the main fuse beside the rccb.

If the main fuse doesn't blow, than return back the main fuse. Than the rccb. Than 1 by 1 ON back the mcb. Till the fuse blow again.

Than you can know where it happen.

Yes; already off all MCB. When inserting the new fuse, sparks come out and the fuse blow.

You're describing a direct short circuit (Live to Neutral).. If you're sure the DB isolator is off then the cable fault is between the kWh meter to the DB..

Have you had any renovation work done recently? Or anyone drive nails into walls ??

They might have accidentally driven a nail into the Live/Neutral cables thus blowing out your fuse..

If shorted, but not trip TS will be able to enjoy HIGH electric bill, but before that a fire may also happen if the fuse are not blow.

Something have shorted.. If not it won't spark. Perhaps someone stealing your electric, or internal got shorted. Check how fast your meter going (if LED is faster the blink mean high consumption, if analog you see it turn like F1)

Or did you do "creative" wiring to have your bill reduced?