Smoke Alarm on a fused spur

[jeffturl]

I was looking to add a smoke alarm running off the mains, when I was looking at it today there is a 2 gang double socket in the room above where I want to put the alarm. Upon lifting the floor boards in the room above, I founf the location i wanted the alarm is far from the lighting ring, so am i allowed to create a fused spur off the Main ring for the smoke alarm?

I would normally wire the alarm with a continual live from a ceiling rose, but can I wire the alarm to the ring main?

Is it allowed to have a fused spur under the floor boards? Or will I have to bring it to a faceplate with access to the fuse into a all mounted back box?

Should I put in a switched or unswitched spur for the alarm?

Am I correct in that it should be 2.5mm to the spur and then 1.0mm to the alarm from the fused spur.

Many Thanks
Jeff

 

[Taylortwocities]

I would not put a smoke alarm on a fused spur. If the fuse goes, or it gets switched off then you won't know.
Thats why its better to use a lighting circuit, you'll always notice that if it didn't work.

For your other queries:

Is it allowed to have a fused spur under the floor boards? Or will I have to bring it to a faceplate with access to the fuse into a all mounted back box?
NEVER put a fused spur under the floor, how will you access it if/when the fuse goes!

Should I put in a switched or unswitched spur for the alarm?
Unswitched, but use a lighting circuit
Am I correct in that it should be 2.5mm to the spur and then 1.0mm to the alarm from the fused spur.
Depends on the fuse size, but you'd probably use a 3A fuse, so 1mm is OK, but use the lighting circuit