DIY Doctor UK DIY Forums

I expected to find a guide which would answer this, but have failed so far.
Is it ok for cables to go through side walls of pattresses?

An external pir light is powered via a fcu as a spur from a double 13A socket on the domestic ring circuit.
I see no problem with this other than that the pir light has no switch and the fcu is also unswitched.
To reduce nuisance triggering, I'd like to replace the unswitched fcu with a switched fcu.

Removing the covers to socket and fcu (with power off, obviously), I see that the wires joining the socket to fcu go horizontally through the walls of the pattresses/back-boxes.

Is this correct?
Should the cable between socket and fcu instead (a) run vertically down the wall (through conduit) and horizontally below floorboards?
This seems a little overkill - how about (b) just running through the back of the pattress, through a horizontal channel in the wall behind the fcu and in through the rear of that box?
If (b), is any conduit necessary?

Thanks, newbie

I find it difficult to envisage what you have. There are many sites that give the safe areas allowed for cables and I will admit even though I know what is allowed I got caught out in my house when the strappers between two way light switches went horizontal rather than up the wall and down to next switch even though it complied.

There should be a means to isolate any circuit but since with a FCU one can draw out the fuse and put a lock through the fuse carrier likely it would comply.

I am told you can post pictures maybe that's best way to show what you think is wrong.