Power supply for a conservitory

[FlickMySwitch]

A friend of mine is wanting to rewire his house and is getting a 17th edition split board RCD protected consumer unit.

He is wanting an extension/conservitory at the back of the house at some point in the future.

He'll probably want heat/lighting and power in there i assume so what would be the best thing to recommend to him?

He's gonna need some sort of supply to tap into at a later date.

10mm T&E sub main to a small 4-way consumer unit with normal mcb's. Say a 45A MCB was protecting this board would that be acceptable baring in mind the sub main would be supplied from the RCD proected way from the main DB. Or would a local DB have to be RCD protected also?

 

[Brian 157]

Is it possible to run cables between the CU and potential conservatory location & leave them coiled under the floor/above ceiling ready to be pulled through & connected when it happens? I did this for a mate a few years ago, still hasn't got a conservatory but there's a couple of 2.5 T&Es under the kitchen floor ready to be pulled through for the ring circuit if it's ever built...

 

[Evans Electric]

I'd say a 10mm T/E and 4 way Bd would be way over the top TBH . Will he be growing canabis plants in there ? You're looking at a 60 amp supply there .

The least for a conservatory would be a 2.5 radial to a socket, with a spur unit for the light.

 

[Doc Hudson]

I'd say a 10mm T/E and 4 way Bd would be way over the top TBH . Will he be growing canabis plants in there ? You're looking at a 60 amp supply there . The least for a conservatory would be a 2.5 radial to a socket, with a spur unit for the light.

I think Evans Electric has a good point there. Wouldn't a 10.0mm cable be a very expensive option with the current copper prices?

Doc H.

 

[ian932]

He'll probably want heat/lighting and power in there i assume so what would be the best thing to recommend to him?

10mm and a 4 way CU sounds OTT for that.

Assuming its electric UFH which is 120W - 200W per square meter then a couple of sockets with a light load (telly, radio, lamps) you can work out the demand if you know roughly how big the conservatory is going to be.

Say:

4m x 4m = 16m x 200Wp/m = 3.2kW = 13.9A. - No diversity allowed

Some socket load 1000W would be generous so with 40% diversity = 1.74A

Fuse spur the lighting, so say 200W inside and 200W outside 66% diversity = 1.15A

Total demand 16.79

So a 2.5mm radial left coiled near by would do on a 20A trip or whack it up to 4mm and you can go to 32A.

But a better job would be to run a 1.5mm for the lights as well so you get some discrimination.

 

[FlickMySwitch]

Thanks for the reply guys, ok i'm OTT on the plan. However i possibly haven't explained this well enough either. The house has a mini extension as it is already, its attatched to the back of the house but they plan to knock it down and build a bigger one. All the ground floor is concrete and there would be no where to leave cables safely in this room so thats why i was thinking of putting some sort of mini consumer unit in there ready for them to tap out when they come round to doing it.