Ring Main Tripping Rcd And Connected With Main Earth

[captaincaveman]

Hi you beautiful people.
Just been looking at a rather confusing and disgusting job in a two floor ex-council house and wondering if anyone could give me any ideas (apart from walking away from it).

• The ring has been tripping the RCD (main switch)
• Live and Neutral have both failed IR test to earth
  
• I split the ring at 4 sockets starting at furthest point to try and locate the fault but each socket is showing 1 leg of ring to be ok & 1 leg to fail IR test. This would suggest to me they are all on radials from a single point then spuring off to downstairs from each socket or there are multiple failures?
• I tried to trace the cables using a circuit finder but the device kept strobing to show live (or as i believe to show it's looping). I did a continuity test between ring live and main earth with everything disconnected (TNS) and got a reading of 1.4Kohms. If there is any continuity between live and earth on a tns does this mean the ring is touching the water pipes and going outside for a walk?
• I managed to have a look under the bathroom floor to find one leg which seemed ok at that point. Other sources of water I'm thinking of are radiators, boiler (out of use) and pet urine.

I had to leave the property until the customer cleared the rooms of junk, poo and urine so i could get in them before I could do any more. A lovely lady but she thinks she's a witch with a dozen cats, dog and crow (and lots of flies). Apparently 13 electricians walked away so half of you probably know where i'm talking about lol.

 

[Wonderwall]

My guess , and it's only a guess, is that there is joint box hidden somewhere which has become damaged or saturated. Does your LxL ExE NxN continuity make any sense? If you can use cables which are reading clear and maybe make two radials and leave any bad cables disconnected and made safe , at least you can get some power on.
Dosent sound like a nice environment to work in Make sure you get paid accordingly.
Good luck

 

[Pete999]

Hi you beautiful people.
Just been looking at a rather confusing and disgusting job in a two floor ex-council house and wondering if anyone could give me any ideas (apart from walking away from it).

• The ring has been tripping the RCD (main switch)
• Live and Neutral have both failed IR test to earth
  
• I split the ring at 4 sockets starting at furthest point to try and locate the fault but each socket is showing 1 leg of ring to be ok & 1 leg to fail IR test. This would suggest to me they are all on radials from a single point then spuring off to downstairs from each socket or there are multiple failures?
• I tried to trace the cables using a circuit finder but the device kept strobing to show live (or as i believe to show it's looping). I did a continuity test between ring live and main earth with everything disconnected (TNS) and got a reading of 1.4Kohms. If there is any continuity between live and earth on a tns does this mean the ring is touching the water pipes and going outside for a walk?
• I managed to have a look under the bathroom floor to find one leg which seemed ok at that point. Other sources of water I'm thinking of are radiators, boiler (out of use) and pet urine.

I had to leave the property until the customer cleared the rooms of junk, poo and urine so i could get in them before I could do any more. A lovely lady but she thinks she's a witch with a dozen cats, dog and crow (and lots of flies). Apparently 13 electricians walked away so half of you probably know where i'm talking about lol.

Have you done resistance readings r1 r2 rn and tested for R1+R2Bwith the conductors dissconected from the CU as pr GN3, OSG etc

 

[Deleted member 9648]

Regardless of difficulties it's a fault find the same as any other,break the circuit down and test in a logical manner until you isolate the fault(s). It's easy to get confused and over complicate things, but if you gradually break the circuit down it will end up making sense.
You have my sympathies, I recall a fault in a similar property crammed with filth and junk. There was one room which it was only possible to open the door just enough to see inside and it was stacked to the ceiling with junk. The mystery was how it all got in there as the only door opened into the room and could only be opened a foot!
The fault turned out to be a rat chewed cable which was clipped down a cupboard and dropped under the floor.
Incredibly after we left the tenant complained to the landlord that we had left 'a mess' !

 

[marconi]

You might want to attend this job in disposable coveralls - plenty of suppliers on line after a google 'disposable coveralls' and gloves, avoid touching your face and eyes, and protect any cuts or blisters, disinfect your work boots after visiting and wipe your tools and test kit with 'sani cloth 70' disinfectant wipes. Wash your hands thoroughly with soap in running hot water straight afterwards. Have a shower/bath straight after the job with a few drops of tea-tree oil in the water. Of course eat before attending and don't accept any drinks from the householder or use her facilities.

My wife is a nurse hot on cleanliness and infection control and the above is what she would do in your circumstances . You never know what strains of bacteria hazardous to health are lurking.

 

[Pete999]

Hi you beautiful people.
Just been looking at a rather confusing and disgusting job in a two floor ex-council house and wondering if anyone could give me any ideas (apart from walking away from it).

• The ring has been tripping the RCD (main switch)
• Live and Neutral have both failed IR test to earth
  
• I split the ring at 4 sockets starting at furthest point to try and locate the fault but each socket is showing 1 leg of ring to be ok & 1 leg to fail IR test. This would suggest to me they are all on radials from a single point then spuring off to downstairs from each socket or there are multiple failures?
• I tried to trace the cables using a circuit finder but the device kept strobing to show live (or as i believe to show it's looping). I did a continuity test between ring live and main earth with everything disconnected (TNS) and got a reading of 1.4Kohms. If there is any continuity between live and earth on a tns does this mean the ring is touching the water pipes and going outside for a walk?
• I managed to have a look under the bathroom floor to find one leg which seemed ok at that point. Other sources of water I'm thinking of are radiators, boiler (out of use) and pet urine.

I had to leave the property until the customer cleared the rooms of junk, poo and urine so i could get in them before I could do any more. A lovely lady but she thinks she's a witch with a dozen cats, dog and crow (and lots of flies). Apparently 13 electricians walked away so half of you probably know where i'm talking about lol.

Sorry Cpt caveman wasn't trying to imply you didn't know how to test a RFC, should have read the post properly, yes I do know where you are coming from, had plenty of experience of hovels during my time.

 

[Dan]

You might want to attend this job in disposable coveralls - plenty of suppliers on line after a google 'disposable coveralls' and gloves, avoid touching your face and eyes, and protect any cuts or blisters, disinfect your work boots after visiting and wipe your tools and test kit with 'sani cloth 70' disinfectant wipes. Wash your hands thoroughly with soap in running hot water straight afterwards. Have a shower/bath straight after the job with a few drops of tea-tree oil in the water. Of course eat before attending and don't accept any drinks from the householder or use her facilities.

My wife is a nurse hot on cleanliness and infection control and the above is what she would do in your circumstances . You never know what strains of bacteria hazardous to health are lurking.

Very very wise. I have a touch of OCD and kinda carry out those procedures even after coming from the cinema or something.

 

[ruston]

You might want to attend this job in disposable coveralls - plenty of suppliers on line after a google 'disposable coveralls' and gloves, avoid touching your face and eyes, and protect any cuts or blisters, disinfect your work boots after visiting and wipe your tools and test kit with 'sani cloth 70' disinfectant wipes. Wash your hands thoroughly with soap in running hot water straight afterwards. Have a shower/bath straight after the job with a few drops of tea-tree oil in the water. Of course eat before attending and don't accept any drinks from the householder or use her facilities.

My wife is a nurse hot on cleanliness and infection control and the above is what she would do in your circumstances . You never know what strains of bacteria hazardous to health are lurking.

That is sound advice . I carry a 'squirty' bottle with diluted domestos in it for the reasons you have stated and clean my boots , particularly the soles before I get back in the vehicle.
I only take the minimum of hand tools onto the job and clean them before the go back in the tool box.

I have not always done this , especially when I was young and fit, but it is a mistake not too.
I would not do a job like that now to be honest. Life is too short.

 

[captaincaveman]

Lots of great advice guys thanks. I have indeed paid a visit to stock up with disposable gloves, shoe protectors, hand soap etc. and my tools are going to stay in the car when i return. The customer has hopefully cleared the rooms or it will be a short visit. Wirepuller, I always try to break it down logically - but when you have flies trying to get in your nose and cats peeing on you it's a bit distracting. I have to keep going back to my car to think and have a smoke to get fresh air lol.

Ideally I want to identify which leg in each socket goes to which leg in each other socket so I can deduct the cable path and then area of fault but I can't do it via continuity by crossing conductors as they all fail insulation test. I can't do it by circuit finder as described so I'll have to do it with an lead extension. With the room cleared hopefully I'll be able to do that (and find more sockets). I reckon I'll have to get her to contain the pets elsewhere though as they keep playing with my leads and are a hazzard.

Just looking at a diagram i've done though I'm finding it hard to recreate a cable path in my head that makes sense. I'll have a brew and another look but would be grateful for any suggestions... (bearing in mind there could be more sockets) The less time i'm in the healthier i'll stay

 

[Dan]

I'm going be honest here and say I'd walk I think, no man needs to suffer that. I'd even tell them clean the bloody place up and they might find somebody willing to work in there becaus if after 13 sparks she hasn't got the message I can't see her cleaning it for you.

 

[Lucien Nunes]

Hang on a minute. 1.4kΩ ring L to MET? That's a big fault! At 230V it would dissipate 230²/1400=38W i.e. the heat of a largish soldering iron and hence probably show itself pretty soon (a carbonised rat will only function as a heating element for so long before either crumbling apart or setting fire to the house). Alternatively it is a mis-connected load that is running to earth instead of neutral but surely then the RCD would have tripped immediately it was connected.

I'm assuming the neutrals were disconnected at the CU when you did this test of course? Otherwise a normal load still plugged in somewhere will show a reading to E as well as N via the supply.

Is the IR fail at each faulty leg the same resistance? If so, then it does sound like one fault with multiple legs incestuously interconnected to it. If not, then I think Mr Rat will have had a hand (or tooth) in creating this problem, as he is known to enjoy sampling multiple cables in a single installation in search of the tastiest.

 

[captaincaveman]

Hang on a minute. 1.4kΩ ring L to MET? That's a big fault! At 230V it would dissipate 230²/1400=38W i.e. the heat of a largish soldering iron and hence probably show itself pretty soon (a carbonised rat will only function as a heating element for so long before either crumbling apart or setting fire to the house). Alternatively it is a mis-connected load that is running to earth instead of neutral but surely then the RCD would have tripped immediately it was connected.

I'm assuming the neutrals were disconnected at the CU when you did this test of course? Otherwise a normal load still plugged in somewhere will show a reading to E as well as N via the supply.

Is the IR fail at each faulty leg the same resistance? If so, then it does sound like one fault with multiple legs incestuously interconnected to it. If not, then I think Mr Rat will have had a hand (or tooth) in creating this problem, as he is known to enjoy sampling multiple cables in a single installation in search of the tastiest.

I haven't tested the system energised as she said there were a lot of sparks/bangs when one of the previous elecs tried it. when I tested continuity from ring live to main earth i did it directly from the ring live to distributers earth with EVERYTHING disconnected including bonding. Like I say, This would suggest to me the live is earthing via pipework? At first I thought the fault lay where the cables entered the metal corroded ccu through an unprotected hole but on closer inspection the damage was superficial (& yes I protected the hole afterwards - BTW, where can you get hole protecting rubber/open grommet as i couldn't source any?)

What confuses me is there is only 1 ring (which runs along the upstairs as it is concrete downstairs). Now, if that is spurred why has that downstairs socket got two legs rather than just the one? It must be in a ring then but with multiple faults. Maybe Mr Rat is indeed...

 

[Richard Burns]

Cats have been known to pee on sockets as marking and so get them wet and fail IR tests, especially if they are uncontrolled male cats. Maintaining an IR test running and seeing if the value increases may be an indication of "water" on the circuit!

A ring on one floor can often be wired up and down as required so your layout could be something like this.
However there are various different wiring methods dependent on the age of the wiring that could produce different results, however having two cable at each socket tends to indicate this more normal arrangement.
However unfortunately this is only one possible option and it has been known! for people to wire things fairly unconventionally or illogically.

A resistance to supply earth from an unconnected line conductor does seem to indicate a connection to earth but this coudl be from a damp house with a the line touching the wall or a metal pipe or any number of other possibilities, probably best to stay with the circuit itself at first, as a connection to a cpc in the circuit that is supplementary bonded in the bathroom for instance would give the same result.

 

[captaincaveman]

Cats have been known to pee on sockets as marking and so get them wet and fail IR tests, especially if they are uncontrolled male cats. Maintaining an IR test running and seeing if the value increases may be an indication of "water" on the circuit!

A ring on one floor can often be wired up and down as required so your layout could be something like this.
However there are various different wiring methods dependent on the age of the wiring that could produce different results, however having two cable at each socket tends to indicate this more normal arrangement.
However unfortunately this is only one possible option and it has been known! for people to wire things fairly unconventionally or illogically.
View attachment 33200
A resistance to supply earth from an unconnected line conductor does seem to indicate a connection to earth but this coudl be from a damp house with a the line touching the wall or a metal pipe or any number of other possibilities, probably best to stay with the circuit itself at first, as a connection to a cpc in the circuit that is supplementary bonded in the bathroom for instance would give the same result.

Thank you very much for your time Mr Burns. Appreciated! I did a simular plan (Above) but not nearly as smart. The blue is where I think the fault lies according to my readings. If I get access to the sockets I will have a better idea. One thing that doesn't make sense on my plan is I'm sure socket 4 had one good & one bad leg. I had to lean over a table to check it before so if it's cleared now I'll have to check it again. It wouldn't suprise me at all if the cats or dog was to blame. Also there is a lot of moisture in the air (due to urine and no windows open) so you could be right with the line to earth thing

 

[marconi]

'No problem can withstand the assault of sustained thinking' [Voltaire]

 

[Richard Burns]

If that is how you think the ring is faulty then run a cable from socket two to socket five and disconnect the potentially faulty legs. The ring should then test as a no fault ring and if you do a full ring test then you can ensure that other sockets suspected to be OK are in fact on this reduced ring.

Then you can concentrate your fault finding on the suspect cables and ignore the rest.

 

[marconi]

BTW, where can you get hole protecting rubber/open grommet as i couldn't source any?)

Try: https://www.tlc-direct.co.uk/tcl/search?query=grommets&Submit=Search

 

[Dan]

Try: https://www.tlc-direct.co.uk/tcl/search?query=grommets&Submit=Search

Or our forum sponsors www.cef.co.uk who gives a discount for forum members.

 

[Lucien Nunes]

Also there is a lot of moisture in the air (due to urine and no windows open)

Moisture alone will not give you a reading of 1.4kΩ unless the whole circuit is underwater. 1.4MΩ yes, but not 1.4kΩ. If that reading is correct, then there must be some other mechanism, such as a 'contaminated' fitting that has tracked, carbonised and is now a charred heap of stuff instead of a plastic accessory. You mention sparks and bangs - where from? If from the DB, then probably the MCB was reacting to a hard short and the 1.4k is what's left now the fault has burnt itself out. One way or another it ought to be visible when you reach it.

 

[captaincaveman]

Try: https://www.tlc-direct.co.uk/tcl/search?query=grommets&Submit=Search

Ah! It's called grommet strip! Was wondering lol. sweet cheers