Circuit breaker tripping

[lemonjelly]

This happens sporadically, but when it does it trips several times, usually in the evenings and then it will be okay for a few weeks. It even trips when I’ve turned the main fuse off when it’s playing up. I feel that it might be happening more in wet humid weather but I think it’s tripped in dry weather a few times too. I’ve gone through the unplugging everything routine, still trips. It’s an old unit. 

Any suggestions greatly appreciated before I let the locals at it, cheers.

Edited August 8, 2019 by lemonjelly

[wayned]

The first thing that I would do is replace the circuit breaker and see if itstill happens before demolishing your place trying to find an intermittent problem.

[Singhajon]

Is it a RCD or MCB?

 

[daveAustin]

Possibly dead short. Go further than unplugging, need to knock all breakers off and then back on one by one, though might not reveal itself if intermittent. Wet weather faults often wet external circuitry; ie, outside sockets/pump/outside lights etc.

[sunnyboy2018]

Replace 

[Crossy]

Can we have a photo of the offending beastie please.

 

But if it's old I would go with the suggestion of a replacement unit first, they're not expensive.

 

Intermittent trips can be a nightmare to diagnose ????

 

[lemonjelly]

5 hours ago, Crossy said:

Can we have a photo of the offending beastie please.

 

But if it's old I would go with the suggestion of a replacement unit first, they're not expensive.

 

Intermittent trips can be a nightmare to diagnose ????

 

Here’s the circuit breaker, god knows how old it is. Is it RCD or MCB?.... no idea. I don’t want to replace the whole box if possible as it’s rented accommodation and the landlord is averse to spending money.

[Crossy]

If it's the "Green" unit that's tripping it's an RCD/RCBO. What trip value is the knob set to?

 

[lemonjelly]

If it's the "Green" unit that's tripping it's an RCD/RCBO. What trip value is the knob set to?
 

I’ll take a look at the trip value when I get home this evening, but it even trips if I set it to “Direct” which is dangerous I know


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[Crossy]

Just now, lemonjelly said:

but it even trips if I set it to “Direct” which is dangerous I know

 

I think it's busted then I'm afraid.

 

You should be able to get a "Safe-T-Cut" unit that will fit in the space but they are not particularly cheap. Maybe time to get the landlord involved (go 50-50 on a replacement).

[lemonjelly]

2 minutes ago, Crossy said:

 

I think it's busted then I'm afraid.

 

You should be able to get a "Safe-T-Cut" unit that will fit in the space but they are not particularly cheap. Maybe time to get the landlord involved (go 50-50 on a replacement).

Cheers Crossy, I was hoping it’d only be the breakers inside the box but I guess there’s more in there that’s fckd, I’ll take a look on lazada and see how much a new unit costs..... cheers again ????

[Rimmer]

I had a similar situation with a 60a main switch under my transformer, turned out it was heat build up inside the enclose that housed it and it was going into a slow overload condition, fixed it by shading the box, not probably your problem but just an interesting little story on heat build up inside a metal enclosure 

[Singhajon]

Is it tripping with all the outgoing breakers switched off

[lemonjelly]

4 hours ago, Singhajon said:

Is it tripping with all the outgoing breakers switched off

It was tripping with the main fuse switch off.... bizarre 

[Singhajon]

It sounds like a Neutral earth fault which can be a bugger to find. The trip is very sensitive 5-20mA. Would be good to have a peak inside that box.

[wayned]

13 hours ago, Crossy said:

 

I think it's busted then I'm afraid.

 

You should be able to get a "Safe-T-Cut" unit that will fit in the space but they are not particularly cheap. Maybe time to get the landlord involved (go 50-50 on a replacement).

Right, the landlord will have the electrician double his quote and he'll agree to pay 50%.  I am the ultimate pessimist!

[bankruatsteve]

While it does appear to be an ancient unit that should be replaced, a new unit will also trip if it is a N-E fault.  The most likely place for N-E fault is in the outlet/switch box full of critter crap/eggs/nest/etc.  Starting with outside boxes, pull the cover and the guts to check for stuff that shouldn't be there.  You can leave the power on as long as you take care where you grab things.  I'm guessing you have one, probably several, in need of a vacuum.

[Crossy]

it wouldn't hurt to clean out switches and outlets, but it trips when set to "Direct" (Post #9) suggesting that it has died the death.

 

If he can find a sparks with an insulation tester a proper job of diagnosis could be done of course.

[Pdavies99]

On 8/9/2019 at 4:43 AM, lemonjelly said:

Here’s the circuit breaker, god knows how old it is. Is it RCD or MCB?.... no idea. I don’t want to replace the whole box if possible as it’s rented accommodation and the landlord is averse to spending money.

Wow!! That's old!!

[Crossy]

A thought.

 

It's not totally clear from the photo but the incoming MCCB is 30A, the RCBO seems to be a much lower current. 

 

It may be going out on over-current rather than leakage, any new appliances installed recently?

 

 

 

[lemonjelly]

34 minutes ago, Crossy said:

A thought.

 

It's not totally clear from the photo but the incoming MCCB is 30A, the RCBO seems to be a much lower current. 

 

It may be going out on over-current rather than leakage, any new appliances installed recently?

 

 

 

No new appliances recently added, it was tripping with everything unplugged and even with main fuse switched off. Local sparky’s already had a peek and reckons it’s had it. Landlord has to buy a new one haha..... 

[mikecha]

Land lord spend on a new box or a fire then he has nothing ,

 

can also be ants check this they get into terminals and cause problems .

[Sumarianson]

It is not an MCB or as you call it a breaker. It is a Residual current operated device, ancient Aztec from my point ( I am an electrician (NICEIC and Part P) get a new board complete with Mcb's & RCD rated at 100mA and make sure the installer has the necessary equipment to test the installation (multi function tester) and provide a certificate (if such a thing exists in this wilderness) the certificate will show any problems existing. Otherwise chat with the electrical contractor. Don't give the job to a guy with flip flops on a honda 125 with a phase tester and a pliers.

[The Theory]

21 hours ago, lemonjelly said:

It was tripping with the main fuse switch off.... bizarre 

Replace it with a new one. 

[Crossy]

9 minutes ago, Sumarianson said:

It is not an MCB or as you call it a breaker. It is a Residual current operated device, ancient Aztec from my point ( I am an electrician (NICEIC and Part P) get a new board complete with Mcb's & RCD rated at 100mA and make sure the installer has the necessary equipment to test the installation (multi function tester) and provide a certificate (if such a thing exists in this wilderness) the certificate will show any problems existing. Otherwise chat with the electrical contractor. Don't give the job to a guy with flip flops on a honda 125 with a phase tester and a pliers.

 

Certificate? 555

 

But I'm wondering why you suggest a 100mA RCD/RCBO when the standard device is 30mA.

 

Thailand is TNC-S with MEN (similar to PME) or TT.

 

[kensisaket]

You need to get someone with a clamp on ammeter to test the current being drawn.  You can disconnect outgoing wires to figure out which line is "shorted" causing the problem.  I've seen some weird stuff here in Thailand; so, opening that box; and, doing a thorough visual inspection may reveal the problem.  At the very least make sure ALL the connections are tight.

[lemonjelly]

You need to get someone with a clamp on ammeter to test the current being drawn.  You can disconnect outgoing wires to figure out which line is "shorted" causing the problem.  I've seen some weird stuff here in Thailand; so, opening that box; and, doing a thorough visual inspection may reveal the problem.  At the very least make sure ALL the connections are tight.

He put a clamp on the cable going out of the meter and said it’s not shorting anywhere


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[Singhajon]

Without looking its a RCBO and wired before the MCCB (Main breaker) as the tripping function works with the MCCB open. I wonder if the installer ran the neutral through the MCCB or direct to the neutral bar in which case it would still trip with the MCCB open on neutral/earth fault. As others have said having a butchers inside the wiring accessories would be first action, no point ripping the whole consumer unit out unless the landlord is up for paying. 

[Skyking]

What do you mean by "main fuse switch off"? Please send a photo of the "main fuse".

There's the possibility of an external fault causing the neutral to have voltage.  Need a multimeter and some knowledge to sort this out. I've had similar perplexing problems when I managed a wireless network in Indonesia. Turned out to be high resistance neutral in the distribution network.

[lemonjelly]

44 minutes ago, Skyking said:

What do you mean by "main fuse switch off"? Please send a photo of the "main fuse".

There's the possibility of an external fault causing the neutral to have voltage.  Need a multimeter and some knowledge to sort this out. I've had similar perplexing problems when I managed a wireless network in Indonesia. Turned out to be high resistance neutral in the distribution network.

I mean the main breaker, it’s 30 amp mccb