Ring main problems

[Drew474]

Hi guys, looking for some advice on the following problem.

So heres the issue:

I was called round to a house because this womens sockets were tripping her RCD, at first it was occasionally, and by the time she a had called me the RCD would not stay on if the ring main was energised.

So i started to investigate, turns out we were dealing with a low reading 20ohms between live and earth (insulation resistance) in the circuit. The problem leg was found and fixed. Now the real issue, on this supposed 'ring' im not getting any continuity on my phase conductors (live and neutral) So again i started to delv deeper into my inspection, i found:

-The kitchen was a recent addition to the home, and sockets appear to spurred from other sockets, and im almost certain there is a joint left in the wall somewhere.
-When attempting a Figure of 8 continuity check, reading at socket outlets were all over the place ranging from 1.08ohms to 2.67ohms, i was hoping to trace out the break using this, but reading were so scattered.
-It then got me thinking that this circuit may actually be two radials, just joined together at the board and put into a 32amp breaker? Bear in mind though that the cable is 2.5mm

Im going back to the house today to try get to the bottom of this, first by testing the circuit from fresh, noting results, then going to try and map out exactly what leg goes where, and check every bit of the circuit for defects. Bear in mind guys, this circuit appears to have had alot of tampering, ie breaking into to and spurring etc.

Any advice from you guys would be great.

 

[keniff]

Maybe set up for r1 r2 test on each leg at the board, make sure u have good readings at every outlet on the circuit, then bang them on a 20amp mcb

 

[telectrix]

suggest taking 1 leg out then finding out which sockets are powered. then repeat for 2nd leg. that should confirm if you have 2 radials and if the ring has been split. solution then is to repair the ring, or split it into 2 20A radials.

 

[Drew474]

Thanks guys, will give it a shot.

 

[Octopus]

Got a similar problem myself at the moment and the house in question does have 2 spurs in a 32A breaker. Not got to the bottom of the "fault" as yet, but very frustrating that the "recent" changes to the house, don't have any test results nor certificates!

Good luck