3 phase temp supply ?

Hi guys, iv been doing loads of basic new build single phase.

The next one is going to be 3 phase and a bigger house. I will treat as normal apart from adding a 3 phase board and balancing on the phases.

The owner has asked me to set up a temp supply. Can I do this but setting up say a garage board and couple of sockets, but using just one phase and not connecting the other two in, obviously neutral and earth will be connected. Thank you for any help