Extending a Ring Main

[CononBridgediyer]

I going to extend the ring main into the loft by using junction boxes. I know what you are all thinking that you are not supposed to extend a ring main using junction boxes and why a ring main to the loft. Firstly, I do not have a socket on the landing and I want to run the cable from the landing into a cupboard on the landing and then into the loft and secondly I want more than one socket in the loft. As the ring main? runs conveniently across the landing between the joists then I thought that it would be easy to break into the main there. My question is that with the floorboards up on the landing I'm staring down at three grey cables which I assume one or two are the ring main. How do I know for sure which is the main and not the downstairs lights as I haven't got a socket in sight and I don't want to take up all the floorboards?

 

[ban-all-sheds]

If you can take boards up you really should do it properly, i.e. extend by taking cables from an electrically adjacent pair of sockets and extending the ring into the loft.

That way you'd know which cables were which, too.

Are the ones you're looking at all the same size?

 

[Damocles]

lighting cables should be smaller. If you think about it, there should only be one ring cable, unless you have found the point where both ends of the ring come up from downstairs. Might be a cable to an immersion. How many circuits have you got?

 

[CononBridgediyer]

All the cables seem to be the same size. In addition, I noticed another thinner green cable next to the three grey cables.

I have four separate circuits - two for lights and two for sockets. However, the combined hot water tank/header tank is in the loft. Immersion heater cable perhaps.

I think I might do it properly and take the cables from adjacent sockets, but my adjacent sockets seem to be the other side of the bedroom from each other. Ah well, better safe than sorry!

Many thanks ban-all-sheds and Damocles for your help so far. I'll let you know what happens when I take the floorboards up in the bedroom this weekend.