Electrics under slab - cutting down the number of conduits

[Bancroft]

Not sure if this should be under the foundations forum or the electrical so I flipped a coin.

 

We will soon be in a position where we can start building our slab foundation.

 

I have a long list of different supplies that need to go in/out of the house, all of which will reside in/under the slab, and I'm doing some fine tuning of what needs to go where.

 

A high proportion of the external supplies will be electrical.  These will go out to connect up to things like the ASHP, car charger, solar input/output, external lighting, car port power, power for the gate/drive lighting, power for the sewage system, etc etc.

 

I was wondering how best to minimise the number of conduits as it looks like our foundation is going to be more conduit than concrete/gravel at the moment.

 

Most of the outgoing electrical supplies will/can be grouped to head off in one general direction (car port/driveway) and I was wondering:

 

Do they all need to go out as separate cables (possibly spread across a small number of conduits), or would it be easier/legal/sensible to just have one cable/conduit from the main house supply out to a secondary switchboard suitably located on the external wall of the house/under the car port? 

 

I expect it may be necessary to have a separate one for the solar (not really sure why I think that but, hey) and any PoE ethernet cables might also want to be in their own conduit, but are there any reasons why all the 'normal' electrical supplies couldn't run from an external switchboard?

[JohnMo]

59 minutes ago, Bancroft said:

wondering how best to minimise the number of conduits as it looks like our foundation

Take some stuff through the wall?

[Alan Ambrose]

We used 3x 100 flexi ducts - one for water, one for 230V, one for data / other stuff. Most heads off to the front of the plot where all the services come in, but a few will go elsewhere. We'll see how well this works later 😉.

[Russell griffiths]

All depends where you are locating the things you talk about. 
ASHP if this is on an external wall of the house then take the wires through the service void in those rooms. 
same with car port if it’s fixed to the side of the house then straight through the wall, if it’s down the garden then you will need a duct. 
why is the solar coming in via a duct unless it’s a ground mounted array down the garden. 
solar panels from roof to an isolator switch then armoured cable to inverter.
all depends on final location. 
I have every item you talk about and it takes up

4-50mm ducts for electric stuff and 2 for comms in and comms out. . 
 

[Bancroft]

16 hours ago, Russell griffiths said:

All depends where you are locating the things you talk about. 

Main supplies are coming into the utility/plant room and most of the equipment needing the supplies externally are the other side of the bedroom/en-suite between the plant room and the equipment.  So, to my mind, it makes sense to put under rather than through the ICF wall.

 

The only solar panels will be above the carport area, hence the inverter etc also being in the car port area - and I don't want batteries within the house.

 

EV charger, driveway and external lights also in the same area.

 

With the ASHP mounted behind the car port we will be putting the inlet/outlet pipework up and over the doorway you can see that gives access to the rear of the house from the car port (top of drawing is rear of house).  The house is single storey so these will enter the house into the loft space above the bedroom.  Yes, we could take all the other cables across there too but I think that would end up looking like a snake's wedding of pipes and cables if we're not careful.  It does give us a joker card, though, if we do forget something fundamental (and important enough to want to drill through the ICF) at a later date.

 

My thoughts are to run one large electrical cable through a duct to a suitably placed/waterproof panel in the car port area where different supplies can then be branched off - rather than lots of smaller cables. The house will have three-phase so done correctly there shouldn't be any issues regarding supply suitability.

 

Another conduit for data and potential water and we can keep conduits to a minimum.

 

Useful to know how you've done it - thanks.  One question though - you have different conduits for data in and data out. - is one of those the fibre supply and the other is everything else or have you split things out some other way?

 

[-rick-]

My feeling here would be to run the incoming to where the EV charger/solar is and then run ducting from there into the house with one mains cable for the whole house (would need additional ducting for comms). Looks like you could run almost the whole route outside the footprint of the house to allow easy access later. But there might be an electrical/building control reason why you shouldn't do that?