Running cables in loftspace

[claret73]

How do you prefer to run cables across a loft space for drops into upper floor of house for light & switch drops? A number of scenarios to consider I presume...

1/ If no boards present & cables must run across the joists trailing to rooms below
2/ Owner may think about boarding loft in future
3/ Insulation present or owner considering insulation in future

Depth of joists less than those of floor levels & so drilling through not an option I presume? 50mm rule?

I'm trying to look at considerations that may become present in future that do not necessarily exist. Surely you have to take these into account in case of new ownership & they wish to change useage of loft from dark dumping space to insulated/boarded storage? Considering protection of cables & time/cost effect of installation.
As always info greatly appreciated.

 

[sparks1234]

Usually enough timber around to get across joists or why not run to where the roof meets the ceilings and clip it there, I would never go across the joists if it is in the main area of the loft as it will get trodden on, as to the insulation look at the reference methods and decide for yourself

 

[ian]

I tend to clip around the edge of the loft and clip to the side of the joist to the lights and switches. I never run across joists or drill through them/

Ian