Planning Q

[RickH]

For a new build … I will request a 3ph supply.
3ph is only required in the garage for some machines & a Solar inverter.

Can/should you use use more than 1ph throughout the house to maintain balance …. I could use 1 for single ph power in garage, 1 for downstairs & 1 for upstairs.
Or is there too much risk mixing the phases.

This is only for me to start thinking about distribution layout.

 

[flameport]

Phase balance is mostly irrelevant for the loads found in a domestic dwelling.

However with a solar inverter you presumably want to actually use a majority of the energy being created, and if you only connect a single phase to the property loads you will only be able to use about a third of the available generated energy. The rest will be exported or wasted.

. I could use 1 for single ph power in garage, 1 for downstairs & 1 for upstairs.

You could, but that's a very poor choice. It will put all of the large kitchen/cooking loads on a single phase, and assuming your 'upstairs' is the usual bedrooms and so on that will have next to nothing on it,.
If you want 3 phase and the benefits from that 3p solar inverter, then you wire the property so that the phases are distributed across the whole property, not segmented into large areas.

 

[RickH]

However with a solar inverter you presumably want to actually use a majority of the energy being created, and if you only connect a single phase to the property loads you will only be able to use about a third of the available generated energy. The rest will be exported or wasted.

Thanks for the comments on balance.
Will consider kitchen on 1 ph, cooker on its own feed on another ….


On generation, not quite the case on my use.

Any excess would be stored in on-site batteries (similar to 20kWh storage I have in my current place).
A 3ph inverter allows me to have a DC EV charger of 25KW, thereby allowing Fast charging at home, and if I want it, the option to run house off the car battery if required (V2X once ratified). … in a ‘Grid Outage’ though my batteries more likely to be used.