Garage & Flat Power

[Tengy]

i'm constructing a large garage block (3 Vehicles) which will require usual power points and lighting for typical garage tools. Above this I intend to form a 1 bed flat with usual power & lighting associated with this. However I want to install an electric wet central heating system for rads & hw supply with a power consumption of 9kw. I have an armoured cable laid from my meter cupboard to the fuse board in the garage which is approx 28m long, the cable is 25mm dia overall and has 4 cables within it, each measuring 5mm dia and made up of 7No copper strands approx 1.5mm dia each.
My house has 2 boards, 1 No RCD protected with 9 ways and 1 No with 7 ways, the mains cable into the house is a '35' size as it is 25m from the street.
Basically can I use the armoured cable from the spare ways in my meter cupboard of which there are 2 to feed the supplies to the new development or am I being optimistic? Any help would be greatly appreciated.

 

[securespark]

Nah.

You need an independent 100A supply from the DNO.

 

[Tengy]

Sorry for the ignorance, but whats a DNO.

 

[Steve]

The people who pipe 'lectric to your house.

Distribution network operator = DNO.

Consider a heat pump to provide heat for the radiators - they operate like an air conditioner in reverse are up to 400% efficient, you'd probably only need a 2kw compressor for that flat, as opposed to a 9kw heating element. The savings would be immense.

 

[Tengy]

Cheers, terminology is different, I know them as 'providers'.
Idea of new supply is daunting, is it likely that my existing cable could be upgraded as is ducted from the street to the house and would be quite straight forward job, and then appropriate sized cable taken via ducting under newly block paved yard to garage/flat for supply there. This way keeps all consumption through house meter which is what I want. All ducting is 4".

 

[Steve]

It could be possible for them to fit a 3-phase service fuse head in your house, and having one phase for your house, and one phase for the garage/flat, but you'd have 2 meters in your house, and i'm sure this would also bring up other complications about earthing and single isolator point etc.

 

[Tengy]

Cheers, seems like I've got my homework to do on this one!