Ring testing - cpc fault - help please

[sidekick]

I have just tested ring circuit and found that the cpc has a break in it.
What is the best way to find out where the break is and what action should i take if not found.

 

[DurhamSparky]

split the ring!!

then narrow it down that way!!! you will find your self at majority of sockets testing between them!!

 

[Mark_Burgess]

1, test between sockets starting from consumer unit (especially if dado rail present) until no continuity.
2, use a TDR (time domain reflectometer) gives you a reasonable distance where the break is from the point of testing.

 

[DurhamSparky]

2, use a TDR (time domain reflectometer) gives you a reasonable distance where the break is from the point of testing.

and they aint cheap!!

 

[Deleted member 9648]

If the L and N are intact it's almost certain to be a break where terminated in a socket....if there are not too many sockets on the circuit it can be just as easy dropping them for a look see until you find the offender,rather than testing...of course if there are lots of points or they are dfficult to remove testing is the way to go.

 

[Des 56]

If the L and N are intact it's almost certain to be a break where terminated in a socket....if there are not too many sockets on the circuit it can be just as easy dropping them for a look see until you find the offender,rather than testing...of course if there are lots of points or they are dfficult to remove testing is the way to go.

Good advise
Its easy to dive into something like this, with tester in hand and brain spinning and end up virtually doing the above anyway

 

[chiplard]

I would disconnect one of the cpc's from the CU, then using a long lead, test continuity from the MET to each socket ( either to screw or use a socket adaptor ). As you go round you will eventually find one that doesn't bell out, it will either be that socket, the socket you tested prior or the cable between them. Quick and simple and no removal of socket fronts until you pinpoint the fault. Once you have rectified check end to end again just to make sure you only had a single break.

 

[sidekick]

Thanks to all for the advice. However, the L and N are intact and after checking firstly behind every socket, all earths appear to be connected ok. Also disconnected one earth at consumer unit and identified sockets with that earth. Then tried other end and identified sockets with that earth.
During these checks it was also apparent that some were single wire or spurs but only found one with three wires feeding a spur.

 

[rocker]

Get the line and cpc from one leg and connect them together at the CU. Using your plugtop attachment for your tester, low-ohm test between line and cpc - the further away you get, a higher reading you should get, until eventually you get no continuity. Between the highest reading and no cont is where your fault is. If it isn't apparent which way they are wired, do the same on the other leg (disconnecting the first leg) and perform the same test on the other sockets. Split the ring between the two highest reading sockets, put each leg in a 16A breaker, bish bash and indeed bosh.

 

[sidekick]

Get the line and cpc from one leg and connect them together at the CU. Using your plugtop attachment for your tester, low-ohm test between line and cpc - the further away you get, a higher reading you should get, until eventually you get no continuity. Between the highest reading and no cont is where your fault is. If it isn't apparent which way they are wired, do the same on the other leg (disconnecting the first leg) and perform the same test on the other sockets. Split the ring between the two highest reading sockets, put each leg in a 16A breaker, bish bash and indeed bosh.

Thanks Rocker. Thats just the way I tested and identified the sockets on each leg of the earth.
To split the ring (ie the L and N) I take it this will need to be under the floor (upstairs sockets) and not possible behind a socket?

 

[pushrod]

.
To split the ring (ie the L and N) I take it this will need to be under the floor (upstairs sockets) and not possible behind a socket?

No , it can be split at a socket. If you are struggling to find the break ie it is not a bad termination at a socket you should be able to narrow it down to between two points then try and trace the approx route out and notice where pictures have been hung on walls, curtain poles, picture rails, even skirting boards etc have been fastened, particularly if an area has been recently decorated.