Ring Main fault - how to tackle?

[Philthefish]

Hi all,

I recently changed over my CU to a 17th edition version. Whilst doing this I noticed that there is just one ring main for the house (not split up and downstairs). During testing, cable insulation tests were ok but there was no continuity through the Live at the CU. The continuity through the N was ok.

When I connect one side of the ring up and power up, all of the sockets in the house appear to be working. If I disconnect this and put the other end of the ring in the CB and power up, none appear to be working. This would suggest a damaged cable (or connection) between the CU and the first (or last) socket on the ring.

The theory is simple. The problem I'm having is identifying which is the first socket this cable calls at - without having them all off and disconnecting all the wires.

Anyone got any experience with this that can make a suggestion?

Thanks
Phil

 

[Hawk81]

I would look at The sockets nearest the cu

 

[SMB]

you do not have a ring.

You have 2 radials. The ring has been broken. Its continuity is broken.

i could advise if your interested to listen.

Regards.

 

[Amp David]

Use a wander lead from the good leg at the CU and take it to each socket. The last socket on this leg will or should have the highest resistance reading.

Pop the socket of just to check its not a spur though.

If you have a socket near to or in a room above the position of the CU, maybe a high chance its the first last socket

 

[Hawk81]

you do not have a ring.

You have 2 radials. The ring has been broken. Its continuity is broken.

i could advise if your interested to listen.

Regards.

He does have a ring with the live broken!! You seem angry in your answer

 

[ringer]

you do not have a ring.

You have 2 radials. The ring has been broken. Its continuity is broken.

i could advise if your interested to listen.

Regards.

Steady on mate -he has a broken ring and is asking for help to fix it.

To the OP, first thing I would do is open up the two or three sockets that are physically nearest the CU. If you still haven't found the problem, then, at the end that does seem to work, remove L from MCB and E from terminal, join them together and take R1+R2 readings at all sockets. The highest reading should be the last socket - but depending on distances there may not be much difference in the readings.

 

[SMB]

When you changed that consumer unit and tested you did not do the required r1 rn r2 tests, because if you had of done those tests and calculations you would not be having this problem.

If you are changing consumer units, and don't have the know how to test, then you should atleast have someone along side you who does know how.

That circuit should not have been energised.

 

[Amp David]

Your right, but his 1 paragraph states hes done his tests, thats how hes found the problem

 

[SMB]

Your right, but his 1 paragraph states hes done his tests, thats how hes found the problem

Sorry I agree.

Ive got me butt stuck up GN3 since yesterday.

 

[Philthefish]

No fighting please!

Can see the logic in your advice re testing resistance from the end of the good cable to locate the nearest/furthest. I'll do that and take it from there. I'll update as I go on.