Looking to install a 10.8kw unit - therefore 10mm electrical cable and
suitable breaker. Question is, do I need to worry about where this
cable goes? The ideal route is going to be under some floorboards,
into an attic and under some loft insulation.

Being a competent diy'er but not a sparky as such, is this advisable?
Is the cable likely to get hot for example?

Any suggestions much appreciated