a little help or pointers in right direction

jon jordan · Mar 1, 2011

hi guys
right bin to a house today rcd trips & stays out on socket circuit in house 1 x ring (up & down ) 32 amp protek mcb 63 amp 30ma rcd

checked every socket in house put sleaving on all earths and checked all connections all now ok but rcd still not switches on .

i didnt take my tester as its in for repair.

what can i do to rectify

if i take cables form mcb ( sockets ) rcd works ok

i have narrowed it down to the cabling some where in the circuit, possible cut or snagged or eaten.

question is how do i find the problem the quickest, can i have your tips on how to do it.

i have little experience with the tester so any pointers there too..

cheers
jon

mechelec · Mar 1, 2011

Without a tester you will struggle to find the fault. What sort of tester do you have and what advice would you like on using it?

peck06 · Mar 1, 2011

If you know where the cables go, break the ciruit in half and in half again until you find between which two sockets you get a low IR reading, then go hunting for it under the floor. Thats what I would do, you will need a tester though.

Kamikaze · Mar 1, 2011

Without a tester your stuffed!

jon jordan · Mar 1, 2011

thanks i got A FLUKE 1652..
i would like to where to start splitting the ring as its up & down sockets on same ring

thanks
jon

piccollo · Mar 1, 2011

jon, after you have isolsted the circuit, disconnected the cables [Ls.Ns.& Es] from their connections & unplugged appliances or make sure every socket/ spur is off, you need to split the circuit where you think the middle may be. It doesn't matter as long as it is split. Now if you havent got your tester [ have you got a bell/ light & battery]. Connect the battery across L & E or L & N at the consumer unit & then go to where you split the ring & connect your light or bell / buzzer across each L & E or L & N [ whichever your battery is connected to] & see if it sounds / lights. You should now have a proved leg. If you had had a Insulation tester you would have just tested across the conductors to prove they were clear. After disconnecting the battery & bell/buzzer / light, connect the L.N.& E [ that you've just proved to the respective terminals & live up the cable [ making sur you open ends are clear / safe. You should now have some sockets live, if all is clear.[ make a not or mark these sockets with tape] If the RCD trips you may have a slight leakage that the battery etc did not pick up, but will assume all ok. Now do similar tests on other leg, which should show / detect a fault. You now have to split this leg & carry out similar tests. You should be able then to liven part of this leg up & so narrow your serch. Hopefully this helps, regards piccollo.

SMB · Mar 1, 2011

To be honest, even once you have found that fault the following tests are required to prove that circuit is safe (no interconnections, correct polarity, and continuity).

Test 1....
End to end test. This will give you the values of r1, rn and r2.

Test 2....
link out Line and Neutral legs of the ring (incoming with out going).
Record values found then r1 + rn / 4

Test 3...
Link out Line and CPC legs of the ring (incoming with out going).
Record values found then r1 + r2 / 4 will equal your R1 + R2. (unless there is a spur and then that highest reading will become your R1 + R2 value).

Have a look in GN3

Regards.