No ring main continuity

[DONKEY]

Hi guys. Did a C.U change yesterday and everything was fine fine except when I came to test ring main continuity on the sockets. It was fine on R1 and Rn ( 0.53) but nothing on R2. Checked all the sockets and there was no obvious loose connection and all sockets tested fine for Zs. The client did not want me to start taking floor boards up ect so I just recorded it on the installation cert. I know i should have done a test before starting but I have real difficulty with this has customers just seem to think that this is an excuse for geting more work. Just wondering if anyone else has come across this situation and what did you do ?

Thanks ...Jon

 

[Barneyb57]

Hmm strange one!!

Could be a damaged cable,, but then I would have thought you would have had another fault on the same cable??

Or has someone tapped into the cable somewhere and you have got a dodgy connection??

Did you have continuity on the Lives and the neutrals,,but not on the earth's,,, So that sort of rules out getting the cables mixed up,,,,as in say..one end of the ring and the immersion heater for instance??

My guess is that somewhere there is a Junction Box and its a Dodgy connection probably on the final leg on one side of the ring main??

 

[Modernelectric]

split it and make 2 radials?

 

[Hutch118]

Thats dodgy in itself Modernelectric, is it not better to find the fault and correct what could be a potentially dangerous problem. I realise that two radials are not unsafe but getting round the fault instead of fixing it is surely the way forward here.

 

[Nick NJH]

Just wondering how you left the job, If you had no Earth continuity this may mean some of the sockets may not be protected, I am guessing you probably checked with a trailing lead for Continuity though, I think I have to agree that there is probably a dodgy junction box somewhere under the floorboards. As mentioned splitting the ring would probably be the best solution if the client is adamant you cant lift any floorboards therefore not allowing you to fully fault find, at least you have done all you can to leave the installation safe then.

 

[Hutch118]

I agree with you both Nick but I suppose if you cant raise floors etc then you should fully explain to the client in a written letter that there is a problem, a way to resolve it and why it should really be sorted out properly.

 

[Nick NJH]

Couldn't agree more, at least then it is up to the client to take action required. Or should that be up to the client to ignore and forget about untill something happens

 

[Hutch118]

Exactly Nick, come across this a lot these days. I was told by my area engineer to document occurences like this then at least there is no comeback for the contratcor if he's done all he can with the situation, informed the client in writing of the problem and defect and left the job a safe as can be expected.

 

[DONKEY]

Hi all. Thanks for your replies. I must stress that there was a good earth at each and every socket but when tested at the C.U ther was no ring continuity on the cpc. My initial thought was that there was a joint box under the fllorboards where one of the earths had come away from the the other but without lifting floorboards this would be impossible to find. I have put this on the installation certificate and will put it in writing to the customer. What more can I do ?

Thanks .. Jon

 

[chippysparks]

I get this problem with rings way too many times, with continuity broken on one of the wires, all i do is report it on the cert/letter and its up to the client then if he/she wants you to sort it!

If the ring is broken completley i put it on two 20a radials.

 

[Barneyb57]

split it and make 2 radials?

splitting it into 2 radials would be ok, But is there still the likely hood that you will still have a socket somewhere along the line with a dodgy Earth??


Aint it funny how things go full circle, years ago when I started from school in the job, we used to use quite often Radials usualy in 4.0mm T&E,,,,,then as time went on they tried to steer us away from radials and use Ring Mains,,,,,now it seems we are being urged to use more Radials??????strange world!!

 

[Mark_Burgess]

I had a very similar problem last week but with the neutral.
Before changing the C.U I did the continuity test and found the fault with the neutral, after doing a wonder lead test I found that the ring was broken somewhere between the last socket and the C.U.
A plumber had put a junction in for a spur to the boiler, the neutral terminal was loose had gone blue/purple with the heat and about 2 inches of insulation had melted!!
Luckily I managed to borrow a Time Domain Refletometer to work out where the junction was in the ceiling.
Damn lucky they were.

 

[andekoch]

Agreed you should let the client know in writing of the problem and what needs to be done to rectify it as well as noting it on the cert.

You need to be able to show that you have done all you can (reasonable and practicably) to correct the problem since a CU replacement makes you responsible for the entire installation meeting the current regs.

A wander lead connected alternatively to each end of the CPC in the CU and then to each socket neutral will tell you between which 2 sockets the break occurs.

 

[Spudnik]

... since a CU replacement makes you responsible for the entire installation.......

Replacing a CU does not make you responsible for the entire installation provided the certificate AND the PIR label attached to CU is clearly marked "CU CHANGE ONLY"

 

[andekoch]

Replacing a CU does not make you responsible for the entire installation provided the certificate AND the PIR label attached to CU is clearly marked "CU CHANGE ONLY"

Useful to know that since I was always told what I had said above. Perhaps what they meant to say was 'makes you responsible to test the whole installation and note the problems down on a PIR as you would if doing a PIR alone'