Domestic PME, Radial socket outlet problem

[freedomrun]

Domestic PME, have two 2.5mm t&e on a B32 mcb, if this was a ring at sometime then the continuity is broken somewhere and i cannot locate the break. No access to underfloor, no spare ways in the CU, has RCD protection to 30mA. I'm thinking it is not compliant to put two Skt Radial cct's on one breaker even if i downrate to B20? Any advice on what to do here please. Thanks.

 

[DurhamSparky]

FIND THE BREAK...!!

power up one leg of ring and make not of outlets on/off that way you can use your continuity tester set to OHMS to find furtherst points away from DB that will hopefully be the end of the "radial" before the break.

disconnect the cables from the 2 end outlets and dink a 20A in the box...!

that way your not energising a wall or a screw!

 

[freedomrun]

Ok, will do as durham suggests - but is it compliant to run two skt Radials from one 20A mcb?

 

[DurhamSparky]

nothing to stop you other than 20A

 

[freedomrun]

I just thought all circuits had to have individual dedicated over current protection, i would'nt put more than one lighting Radial on a single overcurrent device for instance, but that's why i'm asking for some advice from people with more experience.

 

[DurhamSparky]

perfectly fine...!! as said the only limitation is the size of the MCB

 

[freedomrun]

If i am unable to find the break, lets say it was a JB under the floor or in a ceiling, if both legs of the former ring (if this was ever a ring - have no former paper work to refer to & nothing on CU) are protected by a single MCB, then why refer to a wall or screw being energised?

 

[Engineer54]

If you have two radial runs from a single MBC/OCPD then it is classified as a single circuit, as you can't have 2 circuits fed from the same protective device. Then the protective device has to be sized to the smallest cable (if for example different conductor sizes are present). You quite often see a mains door bell supply, taken from an existing lighting circuit!!

So if you have 2 X 2.5mm T&E radial runs you will need to replace the 32A MCB with a 20A MCB!! ...lol!!

 

[DurhamSparky]

i refere to a screw and wall as the break might be in the wall or a screw may have destroyed the cable...!!

you need to remove the legs that feed nothing from back of sockets!!

 

[telectrix]

what he's saying basically is that when you have located the break between 2 socket outlets, then these 2 outlets must both have their outgoing cables disconnected so that you are not energising the broken section.

 

[DurhamSparky]

alternatively call an electrician who will find break and repair..!

 

[Octopus]

Domestic PME, have two 2.5mm t&e on a B32 mcb, if this was a ring at sometime then the continuity is broken somewhere and i cannot locate the break. No access to underfloor, no spare ways in the CU, has RCD protection to 30mA. I'm thinking it is not compliant to put two Skt Radial cct's on one breaker even if i downrate to B20? Any advice on what to do here please. Thanks.

What tests have you done on the ring/radials?

 

[freedomrun]

I've noted what leg supplies each socket outlet and done a Zs test at each. Done an inspection at each and all connections are secure. As Durham suggests, would i now perform an R2 test with wandering lead to find the furthest point on each leg and disconnect the faulty section from there, check all outlets function correctly and then replace b32 with b20? Thanks.

 

[Guest123]

Which conductor/s is the break in continuity on???

 

[DPhilpott]

Seriously... Find that break, e.g neutral could be snapped, large draw creates arching, not long till fire