Martin Pentreath wrote:

Finally at the moment I have cat5 cables festooned around the cellar.
I have an itching urge to clip them to the overhead joists but I know
this is a no-no and I should be using trays. Will it really make that
much difference if I clip them ever-so-gently?

If you use loose clips (8mm) and space them fairly close
together (40cm max) they will be fine.

--
Grunff