mcb tripping indiscriminately

[deputydoguk]

mcb tripping indiscriminately at varying intervals between instantaneous and 10 hours,
I have a mcb that is tripping on the main ring main downstairs .
I have been all round the sockets and looked for loose wires ect . I have also unplugged all the plugs and gone to bed and it the morning it has tripped so it is not overloaded .
Can someone please explain why it could be tripping and why does it work for hours on end then just trip. I can reset it fine but it may trip straight away or wait for a few hours .
I did find a cracked socket which I have replaced but still no joy
please advise

 

[securespark]

Junction box under the floor which is damp?

 

[deputydoguk]

The main board is a cupboard and the wires go under the floor boards which is now a solid floor , but this was done 10 years ago .
I can not see any junction boxes .
could someone please explain why could it keep tripping and why does it go for hours then trips as this what I cant get my head around

 

[bernardgreen]

but this was done 10 years ago .
I can not see any junction boxes

Cable over a central heating pipe. Insulation worn or crushed between pipe and floor boards. Pipe sometimes.. hot sometimes cold means it expands and contracts , a slight movement but enough on a long pipe to make and break a short circuit.

Or walking heavily on a floor board where the cable is crushed.

Or extreme case ( has happened ) neighbour has tapped into your ring main through a party wall.

 

[bongos]

Anything been screwed/nailed into walls? If so it may have gone through a cable.

Might be time to get an electrician to come and complete an insulation resistance test.

 

[Taylortwocities]

It could be mickey and minnie.

Please lets first double check about this MCB.

What is written on it? HAs it got a test button?

 

[ColJack]

that should have been the first question people...

are you sure this is an MCB and not an RCD or RCBO?

like TTC said, does it have a test button.

secondly..

do you have any outside electrics "tapped" off this downstairs ring such as maybe outside lights or a shed or garage, or a pond maybe?

has it been raining heavily in your area before you noticed the trips?

does it tend to trip more on rainy or damp days rather than sunny ones?

what major appliances are wired to this circuit?

 

[deputydoguk]

Sorry been away
it is a 30amp wylex circuit breaker which is still tripping .
The only thing that is on this ring is 3 double plug sockets . I have been all round the house checking that there is nothing more on this ring main and can not find any thing
The wire is not near any pipework and there are no floorboards as it a solid floor . Today it tripped and when I reset it , it tripped straight away so reset once more and it is working fine
why does it sometime last for hours before triping or trips straight away when reset
I replace my old re-wirable/cartridge fuses with this ciruit breaker .

 

[nozspark]

In all honesty, call a spark out... it sounds like you have some faulty wiring and if you do not have the right type of test equipment you will find it very difficult to find the fault!!

 

[securespark]

The main board is a cupboard and the wires go under the floor boards which is now a solid floor , but this was done 10 years ago .
I can not see any junction boxes.

You won't, unless it's see-through concrete. I have known floors to be filled in with concrete, burying all sorts of joints forever.