Nuisance tripping after splitting a ring main

[Mfctitch]

Evening everyone

Had to re post as I started a post within a post

here's hoping I'm posting in the right part or I have started off on the wrong foot.
Long story
Asked by a friend to look at his friends electrics as the kitchen ring was tripping the RCD.
New colours cable
on 32amp B MCB
one of only 3 on the this bank protected by an RCD
5 double sockets
plus a bank of 6 FCU's

Before I went there I had him remove all the plugs plus and turn off the FCU's
believing that this would help narrow down the problem.
But it did not.
so drove to Leytonstone about 45 mins from me
where we split the ring at a double socket and we believed that we had found a the problem which was a bit of cable in the wall between one of the FCU's and a socket in the cupboard.
all this time the other leg was working fine.
So we managed to replace the cable and we seemed to be on the home stretch, when the other leg started to trip I been there for about 5 hours and it was 9pm by now so turned the ring into a radial thinking this will do until I get time to investigate further.
so left at 10:30pm and everything seemed fine only to get a call today saying that the MCB had tripped but not the RCD and thoughts apart from run.

 

[tony clark]

i would like to know how you get on would be really interested in the final result if you need a second pair of eyes i would be willing to look i think you mentioned your in leytonstone i am originally from walthamstow so still some times in the area.

 

[Mfctitch]

i would like to know how you get on would be really interested in the final result if you need a second pair of eyes i would be willing to look i think you mentioned your in leytonstone i am originally from walthamstow so still some times in the area.

Morning Tony
Thanks for you offer but as I'd said previously now that the kitchen is on a radial and everything seems to be working fine. we will not be going back to the job for a few weeks as I would prefer to tackle the repairs in the daytime and not as we have been doing after work.
But I will keep everyone informed as to the out come

 

[DPG]

I might be missing something here but I thought you still had faults on 2 sections of the ring? Have you isolated both ends of this section? Apologies if I've misunderstood.

 

[FatAlan]

Did the circuit ever work correctly in the first place and was anything done electrically just prior to the issue starting? It’s not something like the neutrals being in the wrong neutral bar of the CU (ignoring your test results).

 

[suffolkspark]

Well this thread is embarrassing should we move it to the arms before jo public sees

 

[telectrix]

Well this thread is embarrassing should we move it to the arms before jo public sees

thread's gone down too far for the arms. let's put it in the feet.

 

[Mfctitch]

Did the circuit ever work correctly in the first place and was anything done electrically just prior to the issue starting? It’s not something like the neutrals being in the wrong neutral bar of the CU (ignoring your test results).

No the ring had ben working perfectly since it was installed which I'm told was a few years ago. and no nothing has been added and no work carried out so no chance of a stray screw or nail being the problem.
as for the neutrals being in the wrong bar no as this would have tripped the other RCD. but cheers for asking

 

[telectrix]

forget all you done so far. get back to basics. split at all points then IR each section.

 

[Mfctitch]

thread's gone down too far for the arms. let's put it in the feet.

In
I'm not sure why you would say it's embarrassing ?

is it because of my experience at fault finding or the fact that no one on here can come up with a step by step suggestion that would solve the issue.
other than get someone in who could solve the problem yet not explaine how to solve the problem if that makes sense
.
And by saying this I'm not implying that people on here don't know their stuff just that fault finding by it's very nature is sometimes complicated.

and again I really do appreciate all the suggestions and helpful comments.

 

[Pete999]

forget all you done so far. get back to basics. split at all points then IR each section.

Totally agree, not rocket science after all.

 

[DPG]

is it because of my experience at fault finding or the fact that no one on here can come up with a step by step suggestion that would solve the issue.

Why do you keep saying no one on here can guide you to solving the issue. Several member have told you exactly what to do and how to break it down. You surely can't expect anyone to say 'it's the bit of cable under the kitchen floor' when you are the only one who is actually on site.

What are you wanting?

 

[ruston]

To be fair as recent as @telectrix post 98 is one of many that is the correct procedure . No one is trying to belittle you.
If you are over tired and stressed you may not be able to think clearly.

 

[richy3333]

In
I'm not sure why you would say it's embarrassing ?

is it because of my experience at fault finding or the fact that no one on here can come up with a step by step suggestion that would solve the issue.
other than get someone in who could solve the problem yet not explaine how to solve the problem if that makes sense
.
And by saying this I'm not implying that people on here don't know their stuff just that fault finding by it's very nature is sometimes complicated.

and again I really do appreciate all the suggestions and helpful comments.

OMG what a complete stramash. 7 pages of getting nowhere. I’ve a 1st year apprentice that could have had this solved. OP - if your qualified and competent why do you need a step by step description of what to do? You’ve had seriously good help and advice on this thread. One can only assume you don’t know what you are doing given the comments made. Splitting a ring final and leaving the ocpd as it was. Your posts suggest you’ve been back to the house lots of times?!

How come you only go at night? Are you a vampire?!

 

[snowhead]

It's unusual to get 2 separate faults in the same cicuit at the same time both causing similar issues, there's most likely a common problem.

Don't take the "Nothings been done recently that might have caused it" as 100% true.
It could be something not as obvious as a shelf recently fixed and a screw through the cable(s), like the fridge pushed hard against the wall.

If it is both legs from the C.U that have faults and if both travel the same route from the C.U, it could be something like a sharp edge of steel capping (if it's capped) pressing on both Cables from original install.
And the capping has now got to the point of just touching conductors to a greater or lesser degree.
Or nicks in both cables from install and damp getting in under the plaster.

 

[l4urence]

OMG what a complete stramash. 7 pages of getting nowhere. I’ve a 1st year apprentice that could have had this solved. OP - if your qualified and competent why do you need a step by step description of what to do? You’ve had seriously good help and advice on this thread. One can only assume you don’t know what you are doing given the comments made. Splitting a ring final and leaving the ocpd as it was. Your posts suggest you’ve been back to the house lots of times?!

How come you only go at night? Are you a vampire?!

Love the (Scottish) word stramash - never heard it before but will start using it if I may, despite being a southerner