Ring final in conduit

[SimonH2]

So 2 x 20mm conduits to each backbox is the way to go?

I would go with white plastic oval conduit. IIRC two off 2.5mm2 T&E will fit up a single 25mm oval. However, the knockouts in most back boxes are only 20mm so you'll need to open up the holes to get the conduit into the box - which is important if you want to be able to get the cables in easily afterwards.

For lighting, it really depends on how many switches/cables are going to be needed. For a single 1mm2 drop from ceiling rose to switch, a 16mm oval will be more than enough. Im my mates bungalow, some of the light switch drops are the widest oval (32mm IIRC) to cater for multiple switches, some of them 2-way so needing a second (3 core + E) cable to the other switch.

I'll second the comment about using deepish boxes. Too many people put in shallow boxes and then it can be problematic getting the cables in safely - especially with low profile fittings like the screwless ones my mate used, or deep fittings like the dimmers he's used, or worse still - low profile fittings with deep dimmers in them.

 

[Iggifer]

Plus, the deeper the box, the easier it is to wire.

A RFC socket feeding a spur in a 25mm box is somewhat of a challenge!

 

[markius]

Thanks for your thoughts folks. It's been really helpful.
I'm going to get the spark in to have a look at what I want and where I want it and also to talk about getting a new CU with a single circuit so perhaps the conduit won't be necessary for the electrical side of things.

 

[markius]

That might depend if you don`t mind being plunged in to darkness ?
Are going the have LED emergency lights with an automatic back up supply ?
What`s your location ? (although power supply can fail anywhere) ?

I was planning on having some form of emergency lighting in the cellar to give an illumnated route to the CU should everything go dark. The rest of the house should be OK without.

Location? I'm in Kent. The room I'm decorating first is the lounge and the CU and incomer are in the cellar. Not sure what you mean other than that!

 

[bernardgreen]

emergency lighting in the cellar to give an illumnated route to the CU should everything go dark. The rest of the house should be OK without

An emergency light on the stairs is a good idea should you need to evacute the house.