Power to 2 outbuildings from single CU way

[jone]

Hi
I'm looking for some advice regarding power feeds to 2 garden buildings - a greenhouse and shed.
I'm aware both are covered by part p and will be getting an electrician involved but I want to check whether my overall design makes sense.

There is limited external access to the existing CU and only one spare way on the non-RCD protected side. I have buried ducting from the side of the house to the 2 buildings in preparation for pulling in SWA runs.
My design allows for 5kw per building with a local CU's (RCD, 16A and 6A MCBs) with local TT earthing.
Distances to the buildings are 20m and 50m - volts drop calcs for 5kw load gives 2.5mm2 and 6mm2 for the SWA runs respectively.
As there is only on spare main CU way I am proposing to run a 10mm (T&E) from CU (40A MCB) in the roof space (run length 12m) to a mini CU fitted with two 20A MCBs and these will feed the SWA runs to outbuildings. The SWA armour will be bonded at the house end only.
Does this sense and is the overall design OK?

Thanks

 

[Spoon]

What is the earthing arrangement for your house?
Why TT the supply?
What did the electrician, who will be testing your circuits, say? Also what did he say about the installation method of these circuits?

 

[suffolkspark]

CU in the roof space? um no? also did you lay any warning tape in your duct trenches?

 

[Leesparkykent]

Doesn't sound good if you want to achieve discrimination.

 

[Taylortwocities]

I'm aware both are covered by part p

All electrical work is covered by Building Regulations Part P.

The legal bit of Part P (the Statutory instrument) merely says this:

 

[UKMeterman]

If I am not allowed to work om ELV systems, do I need to inform building control that I have installed a door bell using a PP9 battery and a transistorised buzzer?

 

[Taylortwocities]

If I am not allowed to work om ELV systems, do I need to inform building control that I have installed a door bell using a PP9 battery and a transistorised buzzer?

That information is contained in the Part P Approved Document

 

[davesparks]

Why not feed both buildings with one distribution circuit?