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.

 

[Mfctitch]

An interesting and novel use of the word 'safe'

I thought so
but as we have no ring and we have established where each leg comes into the kitchen. We have established that round the kitchen is ok. so turned it into a radiul and downsized the MCB for the moment.
it will be something simple as we can not see a mouse chewing though both legs under the floor

 

[Mark42]

... we can not see a mouse chewing though both legs under the floor

Mice love T&E. Or at least in my area (Norfolk) they do.

I tempt them with the finest parmesan, and peanut butter, but still - and despite being considered not unintelligent creatures - they prefer to eat the wiring.

I wouldn't be in the least surprised, if you have mice, that you will find multiple horrors which might well explain everything.

 

[ipf]

It's then a great feeling when the 'A-Ha!' point is reached, which it will be.
Good luck

......and a very happy Christmas will be had by all...….

 

[snowhead]

as we can not see a mouse chewing though both legs under the floor

Never say never,,

Nobody expects the..................

 

[Wilko]

Regarding rats and mice damaging cables, there won’t be just one little mouse you know. They have mates, it could be like some premier league away game .

 

[Mfctitch]

hello everyone
again thanks for all the helpful suggestions last night.
So far so good not tripping on the new radial circuit and unless there is we won't be going back for a week or so until we can go back in the day time. I can't cope with getting home at 1:30 and then getting up 5:30 yes I know I'm a light weight. but when we do I will post on here what we find.
But if anyone wants to guess as to why a perfectly good circuit should get an earth fault on both legs where we are getting 240v. please feel free to post

 

[DPG]

Post deleted by me.

 

[Deleted member 9648]

I assume from a brief perusal of this shambolic scenario that the OP either does not have an IR tester or does not know how to use one. That's fine.....but the trick is to get a person in who does have one and knows how to use it before someone gets electrocuted or the place burns down.

 

[Mfctitch]

I assume from a brief perusal of this shambolic scenario that the OP either does not have an IR tester or does not know how to use one. That's fine.....but the trick is to get a person in who does have one and knows how to use it before someone gets electrocuted or the place burns down.

I always find it better to get all the facts before making unhelpful statements
and As I was always told if you have nothing useful or help to say then say nothing.

And the fact that I had several tips from people who have probably forgotten more than i know yet still could come up with an answer to my problem proves that it was not a straight forward problem and even if I had given in and called on someone else they would have had to follow the same steps that I followed.

I grant you maybe quicker but neither the less the same steps and I would not have learnt anything.

but thank you for your input.

 

[Octopus]

I always find it better to get all the facts before making unhelpful statements
and As I was always told if you have nothing useful or help to say then say nothing.

And the fact that I had several tips from people who have probably forgotten more than i know yet still could come up with an answer to my problem proves that it was not a straight forward problem and even if I had given in and called on someone else they would have had to follow the same steps that I followed.

I grant you maybe quicker but neither the less the same steps and I would not have learnt anything.

but thank you for your input.

What make and model of tester do you have?

 

[Mfctitch]

What make and model of tester do you have?

a Megger 1730
with rubbish rechargeable batteries

 

[Deleted member 9648]

I always find it better to get all the facts before making unhelpful statements
and As I was always told if you have nothing useful or help to say then say nothing.

And the fact that I had several tips from people who have probably forgotten more than i know yet still could come up with an answer to my problem

So what was the answer to your problem? I thought it was still ongoing?

 

[Mfctitch]

So what was the answer to your problem? I thought it was still ongoing?

it still is as it was gone midnight by the time we packed up.
finding what we believe to be the first socket on the ring was easy the harder part was finding the last socket as it was located in a ladder with 6 FCU's with very little slack on any of the cables

 

[Charlie_]

How many section of the ring tested faulty?
Just the 2 legs from the board?

 

[Mfctitch]

How many section of the ring tested faulty?
Just the 2 legs from the board?

in the end yes