Ring main in timber frame house

[Podooser]

I am proposing to use 2.5mm2 cable, run vertically to each back box in 20mm conduit ( both cable to and from socket in one conduit). Cable run will be clipped to joists. Insulation will lie behind conduit ie not surrounded. Does this all sound OK.

 

[JohnD]

Is this a house already built, where you have to poke the conduit down from the floor above? Or is it still in construction?;

 

[Podooser]

It is being built at the moment and is ready for the first fix.

 

[JohnD]

if the drylining isn't on yet, why not run the ring horizontally around the rooms? It will be more economical in labour and materials than going up and down. It also makes it easier to break into the conduit later and add another outlet. Since the conduit is always at the height of the sockets, the cable is in a safe zone.

In kitchens, home offices and workshops, the run can be 150mm above worktop height.

There is also no need to bunch two cables in a single conduit.

 

[Podooser]

I will still need to go up and over the doors. The lounge, dinning room and kitchen are open plan and there are two sets of French doors to outside.

 

[JohnD]

yes, you will. Or under the floor if not concrete.

Are you attracted to the idea of going up and down?

 

[Podooser]

Are you attracted to the idea of going up and down?

No, but someone suggested this and I was not sure myself whether this was the best way to do it.

It will be a concrete floor with underfloor heatingn so no under floor wiring. Will 2.5mm2 cable be sufficient when bunching the 2 cables in the conduit?

 

[securespark]

Are you attracted to the idea of going up and down?

Only with a beautiful woman underneath...

 

[JohnD]

on top.

I like to see a woman taking an interest and working hard.

 

[Podooser]

It will be a concrete floor with underfloor heatingn so no under floor wiring. Will 2.5mm2 cable be sufficient when bunching the 2 cables in the conduit?

 

[JohnD]

Mr Secure will know. I'd have to look at my Rating Factors tables, which aren't to hand.

 

[securespark]

You're laying cables in a solid floor that has UFH??

 

[Podooser]

No. It was an response to one of JohnD's suggestions. [/quote]

 

[Podooser]

I'd have to look at my Rating Factors tables, which aren't to hand.

JohnD did you manage to look this up?

 

[JohnD]

grouping for two multicore cables, enclosed method 3 or 4, is 0.8

so capacity is 20A x 0.8 =16A

I can't find conduit capacities for T&E


But on a 32A type B MCB it gives no leeway for an unbalanced ring.

Just use 2 conduits,one in and one out