Loft light cables

[APE37]

Hi guys, quick question
looking at getting around to installing a loft light at my sisters house and the board is 16th edition lighting on non rcd side. Cables will be clipped to wood work but 1 foot and half roughly will be going between joists to landing light. In this bit it is boarded and I was thinking about leaving on non rcd side, but thinking as the joists are about 75mm do I need to put on rcd side? As I look at on site guide it states cables passing through joists are to be plus 50mm and cables in walls or partitions need to be 50mm plus but as I am running between 2 joists ina ceiling and not passing through any joists to landing light do you think this needs rcd protection as the way I interpret it there are 2 sets of rules for cables in wall and other in ceiling and the rules don't state in a ceiling if rcd is needed when cables run along joist. Or should I take the plus 50mm rule when cable I talked in wall or partition?
Sorry for a silly question but looking to do the best way.
Cheers
APE

 

[Octopus]

I would still question the advice if the help desk. It's the ceiling structure and not a wall!

is it the NICEIC or Elecsa help desk?

 

[Deleted member 26818]

Again, RCD protection for cables above ceilings and below floors is not an acceptable method for providing additional protection.
An acceptable method would be to notch the top of the joist, and then cover the cables with 3mm steel plate.
Another thing to consider, is the depth should include the lath and plaster and floor boards (if there are any).

 

[Geordie Spark]

A ceiling is not a wall IMHO so no RCD needed.

It's a wall lying on its side. :17: