Help - Kitchen Fuse trips every 10 days since last August

[RubberDuckBoy]

Help - since August the fuse in the kitchen keeps tripping - at least once a fortnight but usually once a week. we have had two electrians around but neither has found the fault - but they have cost us more than £300 so far.

The only thing which is common with the fuse tripping is that it invariably happens at night - usually 30 to 60 minutes after we have gone to bed (about midnight) - only once has it happened in the evening when we were both still downstairs.

It has blown when we were on holiday and the house was empty and all the plugs bar the fridge/freezer disconnected.

It is not associated with any specific appliance. We moved the fridge/freezer to another circuit but the kitchen fuse still tripped. We continue to use all the other appliances normally without any problems (washing machine, bread-maker, kettle, microwave, dish-washer (v.light use) etc)

It is not associated with weather - as it has not tripped when the weather has been wet and windy outside.

The kitchen is new - less than 10 years old and was completely re-wired when installed. The main circuit board is less than 12 years old.

There is no evidence of rodent droppings in the kitchen.

I found and fixed a slow water leak to the dish-washer which reduced the frequency with which the fuse tripped - but it has still continued.

All the plugs on the circuit have been inspected and do not show any sign of damage. There is one plug mounted on the kitchen tiles which has shifted a few millimeters showing a dark gap on one side and underneath - this has been inspected by both electricians and re-wired and they have said it is not the source of the problem.

We have had no major work done in the house for over a year - the only stuff I have done is fit a new plug to the upstairs ring-main circuit. The neighbours have also extended their house which required some ground-work (finished in Spring last year)

When the fuse goes it make a distinctive muffled bang sound.

Last night, when the fuse went it appears that it caused a short power-cut because it set our burglar alarm off and caused the cooker clock to re-set itself (cooker is on a different circuit and last re-set when we had a power cut five years ago).

Obviously I am now getting extremely worried, least of all because I do not want any more incidents waking up the neighbours.

Any ideas what the matter be ?

Thanks for all your advice

Rubber Duck Boy

 

[PrenticeBoyofDerry]

I found and fixed a slow water leak to the dish-washer which reduced the frequency with which the fuse tripped - but it has still continued.

What was the frequency prior to this repair, when did you carry out the repair and did the leak manage to get in to the electrical installation?
Have unplugged this appliance, to see if the trip still occurs with it off load and off circuit.?

 

[RubberDuckBoy]

Leak was relatively slow - drop every minute or so - was approx - 200 mm above and 400 mm to the right of the dish-washer socket.

No sign of any water ingress into the socket (lots of dust on top of it) and plug has been inspected by electrician - they did not find the water leak as most of the water was falling behind the cupboard and not on to the water-proof mat we had on the floor of the cupboard.

Rubber Duck Boy

 

[PrenticeBoyofDerry]

Do any of the water manage to find it's way beyond the the waterproof mat.
Like perhaps, through floorboards to junction box beneath?
So who long since repair?
and frequency of trips was prior to repair?
and what type of fuse is it?

 

[Space cat]

Unfortunately, intermittent faults like yours are an absolute pig to track down. I know this because we had one just like yours. The only clue you have is the reduction in the fault rate since you fixed the leak so I would start in that area. Is there any way to get under the floor? (Some houses have enough space below the boards to crawl around.) This would be worth doing anyway in case you have the beginnings of rot down there. Check inside any junction boxes you find.

PS: I'm reluctant to recommend the method I used to track ours down but here goes anyway. I split the ring and moved one half onto a spare breaker then, each time one of the two breakers tripped, I moved the split point around. After three faults I had it down to a short section of ring with just two sockets on it. The rest was easy.

PPS: I found the fault in the back of a socket box. It looked as if the insulation around the live core had failed just where it emerged from the outer sheath allowing live to earth shorts that kept blowing themselves clear. The earth wire came away in my hand.

 

[Alarm]

it caused a short power-cut because it set our burglar alarm off

That needs looking at, as it sounds like the standby battery needs replacing too.

Sorry about that bit of bad news.