Fuse breaker keeps tripping.

[Road_Hog]

I know this will involve an electrician. But over the last two months the fuse breaker has been tripping out, that is the main one, not any of the individual section ones.

If we're awake, there's a sort of sound of a 'pop' from the kitchen and then it trips out. This can happen when no one is in the kitchen and there is nothing running.

It can also happen in the middle of the night, when pretty much everything is off.

A trip to the garage, flip the switch and everything is okay, no fuses blown on any equipment and they all work fine, once the fuse breaker switch has been flipped back on.

We can go for a couple of weeks without this happening, and think it has sorted itself, but middle of the night, it went again, which is painful, as the alarm clock is mains powered, so it can't wait until the morning.

Any thoughts on what it might be. My main problem is that it is intermittent. All mechanics and electricians I've come across, hate intermittent faults, because they never show up when they're testing.

[newshound]

It sounds to me a bit like moisture collecting somewhere. What you say about tracing intermittent faults is correct, but in fact this type of fault often shows up straight away on a test with a "Megger". That's a very easy check and I would think any decent sparkie would be happy to run that and a couple of other checks on a "no promises" basis.

[Martin Brown]

ELCB presumably seeing a leakage current. Smart money is on the kettle, washing machine or immersion heater.

Unplug the kettle completely when not in use and see if it stops.

Unplug everything you can and if that fixes it plug half back in. Repeat until you can narrow the fault to one appliance.

Battery powered alarm clock?

Everyone hates intermittent faults. They usually get worse with time but faults in kettles seem to heal for a while with scale then go again.

[Fredxxx]

A Megger or PAT tester might find the offending appliance.

I have come across, though some time ago though, RCDs that were especially sensitive to transient currents into suppression devices when they were turned on.

[Martin Bonner]

That raises the question: What is it that's actually tripping? An ELCB/RCD, or a main fuse?

[Fredxxx]

Are we talking RCD or MCB?

[newshound]

Also dishwasher and electric cooker.

I agree about unplugging kettle etc overnight, you could also switch off the cooker at the wall.

The sound of a pop from the kitchen is a good pointer and probably eliminates the immersion heater (unless you have an under-sink one).

If it gets more frequent you can also try switching off the kitchen "ring main" overnight (fridge and freezer should survive this time of year).

But I would still be inclined to get an electrician in sooner rather than later. This type of fault is unlikely to start a fire, but it could.

[Mr Pounder Esquire]

I have seen fridges and freezers do this when they are getting a bit elderly.

[The Natural Philosopher]

also mouse chewing wires

[Road_Hog]

Thanks for the replies. It is the MCB, there are no plug in RCD devices at the house.

I will try the kettle, as when we are about when it happens, there always s eems to be a pop from that direction. If it isn't that, I will get someone in, as from what people have replied, it seems that it would be a fairly si mple task to locate the problem.

Fingers crossed it's just a replacement kettle.

[The Natural Philosopher]

MCB?

What took mine out at 4 a m was the candle bulb I had left on in te cooker overhead light..blowing

Now replaced with LED flavour

[Tricky Dicky]

In the first paragraph the OP says it is the main breaker NOT the sub-circu it ones, I take it that means an RCD/ELCB. If he is hearing a pop in the ki tchen it is probably one of those appliances especially one where water is involved. My first suspect would be the kettle with possible water leaking into the socket the lead plugs in, any signs of arcing is a giveaway.

Richard

[tabbypurr]

seems to be a pop from that direction. If it isn't that, I will get someon e in, as from what people have replied, it seems that it would be a fairly simple task to locate the problem.

Random MCB blowing is a bad thing, and a definite fire risk. PAT test or me gger all appliances & test the installation. It's unlikely to be the kettle if its an MCB.

NT

[Brian-Gaff]

Well a process of elimination needed. If no other breakers are tripping this tends to point to one of two things. You have a faulty breaker somewhere which is not tripping when it should, or the one that trips is somehow faulty.

I suspect it might be the latter though your mention of a noise from the kitchen is a little odd. When the Fridge kicks in I can sometimes hear it in our house so although the current of whatever it is is not actually tripping the individual breaker it could be tripping the main one if its got a problem of some kind. as you rightly say, trying to induce such a fault is often frustrating. Also you do not say if this ever happens during the day. If its always at night you need to ask yourself what is there that only operates at night on my system? Brian

[Mike Humphrey]

Earlier you said "the fuse breaker has been tripping out, that is the main one, not any of the individual section ones". It would be very unusual to have an MCB covering more than one circuit - are you sure it's an MCB that's tripping? It might help if you can post a picture of your consumer units (all of them if you have more than one) then we can try and work out what's what with it.

Mike

[Brian-Gaff]

Yes marinated spider moisture collection syndrome. However it does seem odd that it does not happen when people are active in the Kitchen, if indeed this is where the sound comes from, noting the breakers are in the garage.

I assume no rodents are about at the consumer unit or elsewhere nearby? Brian

[charles]

He's probably got a total load Master RCD. Quite common in the '80s. Regrettably we have one. It would be a major effort to replace it with RCBOs on the relevant circuits.

[Fredxxx]

Lets be absolutely clear, is it one of the many MCBs (there are usually

4 to 10 of these) or it is the incoming RCD/switch which has a "test" button on it.

It is possible.

[Bill]

In message , charles writes

I had that and replaced every circuit, all 14, with RCBOs, it was well worth the effort. 2 reasons, now I only lose one circuit if there is a trip and it also made tracking down a long term very occasional fault a lot easier. Providing the original wiring in the consumer unit was done neatly and there is enough space it does not take too long to do. The biggest shock it to the wallet! :-)

>

[charles]

Mine is an early MC CU and I think the RCD input switch is fixed. I'd really have to change the whole CU - as you say the wallet would be seriously affected.