DIY Doctor UK DIY Forums

Hi,

I am looking to fit an additonal double socket (within a house built 1993). I had proposed to pick up from an existing socket but am unsure whether I have a ring or radical circuit. I would ideally like to pick up the feed from a nearby socket that has two sets of cables since it entails lifting less boards than using a junction box.

Can I ask please:

Is there a sure way I can determine whether the curcuit is ring or radical ?

Also, the new socket is to reside in a hollow stud wall. There will be a short run of cable between the socket and the lower horizontal timber as I come up from under the boards. I am assumming even this short cable run must reside in conduit ?

Thanks.

With the power off of course if a ring main the if you measure the ohms between each pair of wires they should be less than 2 ohm. Since it is very easy for a ring to become spurs where faults have occurred better to measure all three cables.

Neutral and line should measure the same and earth slightly higher reading although that is not always the case.

Conduit is not required you could if you so wished plaster direct onto the wires but since many plasters have damaged cables we normally use capping or oval conduit at one time metal capping was norm but because it would now need earthing plastic is now the norm.

Of course all sockets are now protected by RCD and if you were working on an old house then likely you will need to add an RCD at some point.

Theory easy method would be to use Ali-tube cable as then the cable does not need protecting and just using RCD sockets would be enough. However when I tried to buy Ali-tube cable I could only buy by the role which runs expensive so steel conduit, or a RCD FCU at socket it comes from may be required.

Since steel conduit is both hard to bend and needs very deep chase the FCU RCD is most likely the easy way out.

As you can see there are many ways to do same thing and I am sure I have missed some options.