Adding a loft light help.

[barry1873]

Hi all,

I've just moved into a new build house and am planning to floor the loft for some light storage.

My first task is to install a loft light. I have studied loads of threads and diagrams on this topic and thought I was ready to start.

But when I started to look at my ceiling roses they were nothing like what I expected. I was expecting to have a supply in, supply out, switch and light cables in each rose. But what I actually have is just one cable in and the light cable.

When I follow the cables in the loft they all seem to disappear into the walls at some point. So i'm a bit lost. My thinking is that if I used one of the supplies to the lights then the loft light would only work if that light is on as well. Is this correct?

What I do have in the loft though is a double socket. Is this a better bet to try and take power off using a junction box?

Thanks for hte advice!

 

[Taylortwocities]

HAve a look behind your light switches. If there are two (or more) blue wires in a terminal block then the loop in may be in the switch.

That may mean you don't have a lighting live and neutral up in your loft

If the loft is not to be used much, then just run a light and switch and plug it into the socket. Use a 3A fuse.

If you need both halves of your double socket in the loft, then you'll need to install a 3A fused connection unit (FCU/fused spur) to supply your light. You cannot use a junction box to power your lights. They need a much smaller fuse than the one in your socket circuit.


But count yourself lucky. Most people only dream of a socket in their loft!

 

[riveralt]

Hi all,

I've just moved into a new build house and am planning to floor the loft for some light storage.

My first task is to install a loft light. I have studied loads of threads and diagrams on this topic and thought I was ready to start.

But when I started to look at my ceiling roses they were nothing like what I expected. I was expecting to have a supply in, supply out, switch and light cables in each rose. But what I actually have is just one cable in and the light cable. When I follow the cables in the loft they all seem to disappear into the walls at some point.
So i'm a bit lost. My thinking is that if I used one of the supplies to the lights then the loft light would only work if that light is on as well. Is this correct?

If you have one grey cable with brown/blue and earth conductors then it is possible that this lamp is linked to another - (ie they both come on at the same time) So any connection to this ceiling rose will as you say need the other light on to work.
It is also possible that this light is powered from the switch itself - but the same scenario would entail.

What I do have in the loft though is a double socket. Is this a better bet to try and take power off using a junction box?

This is probably your best option provided that the double socket is not already a spur on a ring final circuit. If it is not then run 2.5mm T&E from the double socket to a Switched 3Amp Fused Connection Unit and then 1mm T&E to the Light you want to install.

 

[Taylortwocities]

Ha ha me first!

 

[PrenticeBoyofDerry]

If you have a double socket in the loft, first you need to find out how it is supplied.
1)Is it a spur?
2)a fused spur?
3)or is it part of an extended circuit, possible end of a radial?
If it is either 2 or 3 you can then connect a FCU(5A max) after the double socket outlet, one with a switch will be ideal as this can then be used a functional way of operating the light. Then just connect the the line, neutral across the light from the S/FCU and terminate the CPC (earths).

If it's 1 it would be an idea to fit an 13A FCU before the socket outlet, then does as described above.
Looks like I've been beat to the post twice

 

[riveralt]

Ha ha me first!

Damn ..... nothing else for it....

http://www.pitman-training.com/Courses/courseDetail/faster-keyboarding-part-1

No more one finger ytpin

 

[barry1873]

Wow, thanks for the quick replies.

I have considered just using the socket but ideally I would like to keep that free if possible.

So how do I identify if the socket is " a spur on a final ring circuit"?

 

[riveralt]

Wow, thanks for the quick replies.

I have considered just using the socket but ideally I would like to keep that free if possible.

So how do I identify if the socket is " a spur on a final ring circuit"?

If you don't intend to use the socket then you will have to tap into one of the lighting circuits in the loft either through a ceiling rose that has the live/neutral/earth loop or intersect the live/neutral/earth loop cable with an accessible junction box as per wiki
http://www.diynot.com/wiki/electrics:lighting:single_way_lighting

If your house is a new build you should have been given at least an Electrical Installation certicate and wiring diagrams of each circuit. You should be able to tell from this and wiki
http://www.diynot.com/wiki/electrics:socket_circuits
whether your socket in the loft is part of a RFC or not.

 

[PrenticeBoyofDerry]

So how do I identify if the socket is " a spur on a final ring circuit"?

A little investigation is needed.
Are there any documents for the installation? As this should give you information on the configuration of your installation.
Is the consumer unit labeled up with the circuits?
Also look inside the consumer unit and identify the circuit the socket is on. (isolate the system first)
The size of the MCB/protective device, the size of the cables on the circuit and the number of conductors that enter the MCB will also be helpful.
If there is only one line conductor entering the MCB there is a good chance this is a radial if there are two line conductors and the breaker size is 32A there is a good chance it is a RFC.
But this is not cast in stone, to be absolutely sure you would need to do continuity tests on the circuit.

 

[ban-all-sheds]

I've just moved into a new build house and am planning to floor the loft for some light storage.

Check on the roofing forum.

Some modern roofs are only strong enough to support the weight of the ceiling boards.