Wiring diagram with cable size/spec

[Gunnera]

Hi
Currently trying to get quotes for a PV system, but want to get any major cable runs put in place now while I have parts of the house floor up, so need help in knowing what would be worth putting in place.
Main consumer unit is in the house (100A fuse/ 80A RCD). I would like to install any electrical units required by the Solar system in the Garage, 15-10m away depending on route, but connected to the house.
I would also like a small Consumer unit in the garage to supply Solar stuff and a few lights & power sockets.
Rather than run a cable(s) outside in a trench I currently have the option to get a cable(s) run under my block & beam floor from main CU to the Garage.
I think any Solar installation would be max of 6KWh

Can anyone advice on what cable(s) it would be worth putting in place between main CU & the garage?

Any help appreciated.

Cheers

 

[Mike.J]

Put in a two, three or four way duct then the PV installer can pull through what they like and you have the option in the future to pull in other cables.

 

[Murdoch]

Main consumer unit is in the house (100A fuse/ 80A RCD).

If its an up front RCD you really need to change the fuseboard

 

[Gunnera]

Considered ducting but the breakout through the outside wall into the garage with solid concrete floor involves a few tight bends, so at least getting any larger cables in before I close the floor up would be good.

The main consumer Unit has RCD included within it.

 

[Murdoch]

The main consumer Unit has RCD included within it.

If its an up front RCD any new circuits won't meet 314

 

[Murdoch]

Considered ducting but the breakout through the outside wall into the garage with solid concrete floor involves a few tight bends,

Tight bends and cable are NOT a good idea.

 

[binky]

Keep solar off main board, that can be done by tapping into meter tails with meter tail blocks and install a non-RCd protected mini CU. Cable to garage, your solar at 6kW is going to be around 24Amps which could be done with 2.5mm cable, however I would run a 6mm or 10mm cable as you may change plans for the garage, and the cost of the cable is not much more. Within the garage another mini CU, RCBOs for the other circuits, MCB for the solar - inverters and RCDs don't mix well. DC cabling to the roof, not so easy to spec, but I would run 4off 4mm solar cable runs - mark the ends with tape or the like so you know which one is which. Provided you can use cavities and keep cable 50mm away from any wall surface, you wont have to worry about 'protection' for the cables. Do not run through insulation. It may be easier to use 25mm conduit on the external walls to the attic/ roof, it may also be something you leave to the solar installers.

 

[Gunnera]

Thanks for the advice, think I might run 2x 6mm cables and a small duct with pull wire before closing up the floor then, as you say cost of cable compared to alternate route outside in a trench or getting floor up again make it no brainer.
DC cabling I think I'll leave until I've spoken to an installer, assuming I can find one that's interested, they all seem too busy at the moment, otherwise I might give it a go myself.

Thanks again

 

[binky]

Thanks for the advice, think I might run 2x 6mm cables and a small duct with pull wire before closing up the floor then, as you say cost of cable compared to alternate route outside in a trench or getting floor up again make it no brainer.
DC cabling I think I'll leave until I've spoken to an installer, assuming I can find one that's interested, they all seem too busy at the moment, otherwise I might give it a go myself.

Thanks again

Demand for soalr has shot through the roof. as you can see from the questions on here. There's acytally nothing to stop you fitting solar yourself, the requirement to be MCS registered was only to claim the long gone FiT payments. Octopuss enrgy I believe still ask for MCS cert if you were thinking of using their energy tariff that gives some form of payment for exported solar energy, although last time I looked at what they offer, you were better off using the energy yourself. The only legal requirement is to notify your DNO with a G99 or G100 applicatin and a pretty diagram.