Loft light

[pickles]

Hi again sparky persons, more E-advice required please.

I'm installing a neon light (about 1 meter long) in to a small loft storage space behind a bedroom wall. I'm planning to source the power from the back of a socket in a bedroom which is on a ring main and easy to get at because it's in a stud partition. I know this will need to be run via a fused connection unit. There will only be one neon on the circuit and nothing else at all so i'm planning to use a 3amp fuse.

Some questions for you all.

Is this the right fuse rating, it seems to be the smallest fuse I can get.

So that the fused unit is easily accessible I need to run a length of cable to it from the back of the socket for about 4 meters, clipped to a joist. Is this acceptable. I could put the unit by the socket but this would involve a dusty crawl in the dark to change a fuse. I could put it in the bedroom but it would be long way from the light and far from obvious where the fuse for the light was if it blew. I would know but no future owner would easily work it out. Where i'm planning to put it would make it obvious that it was the light fuse and it would be easy to access as well.

If I can run the cable must I run this in the 2.5mm cable used for the ring main or is it ok to run it in the 1mm cable i'm planning to use for the light circuit.

Thanks in advance for your always excellent advice.

 

[Spark123]

Neon or fluorescent?
As long as the cables are in safe zones, RCD protected where unprotected and concealed less than 50mm from the surface should be OK.
Use 2.5mm on the RFC side of the FCU, you can use smaller after that providing it is suitable for the load.
You can clip direct to battens if you wish, as long as it remains within zones if it is to be concealed.

 

[pickles]

Standard strip light, sort of thing you get in an office, has a little starter in the side. We always call them neon's but I think the correct term must be flourescent.

I will do as suggested but what's the logic of running it in 2.5 to the FCU if the load will be so small, is there an electrical safety type reason or is it just regulation compliance.

 

[Spark123]

The logic is to do with the cable being protected by a 30A/32A device back at the CU, the adiabatic equation may not allow you to use a CPC as small as 1mm. Not as big an issue if the circuit is RCD protected.

 

[pickles]

It is RCD protected, 30ma at CU but I would feel happier in 2.5 if that's best, even if its a counsel of perfection

 

[BS3036]

As the run is 4m, I think you are obliged to use 2.5mm, because of reg 434.2.1 which allows an FCU to be fed by up to 3m of cable protected only by the downstream protective device. But not 4m.