wiring under floor boards

[pb8]

Hi all I've been asked to wire a friends house but it's got a space under ground floor floor boards. Can't remember ever doing one before. Do I need to put cables in tube or are they ok just resting? Can't see anything specific in big book.
Originals just lying there so I'm assuming I'm ok to do same.
Thanks all
Paul

 

[Engineer54]

I think the only reason you find cables clipped to joists in new builds is because they'll be no ceiling boards in place at that time, and all joists would be accessible. Most houses these day's are constructed with solid floors on the ground floor, so all the power/socket cabling will be via the ceiling voids dropping down to pick-up the wall accessories. In a domestic setting, i can't see any problem having cables resting on ceiling boards. You're never going to be able to clip the cables adequately in a re-wire situation anyway....