Extending Loft Lighting

[Moyzie]

Hi. I`ve just joined DIYnot.com and have read a few (very old) posts about extending loft lighting. Sorry if this post is a repeat of previous ones but I`m hesitant about going ahead until I`m clear about my own situation as I`m not an electrics expert.

In my loft, there are lighting and socket cables, which converge in a grey plastic box, which I assume is a junction box (20cm x 20cm). From this box, there is a single cable to a switch and, from this switch, the cable continues to a single bulb in the middle of the narrow loft, where the circuit ends, so I assume this is a `spur`.

I simply want to add 3 bulbs to the left and 2 to the right of the existing bulb, all controlled from the existing switch.

Should I simply put in a new 1.5mm twin and earth supply cable from either side of the existing light? Or should I run 2 separate cables from the switch to serve both sides of the loft? Do I need an FCU for so many bulbs on a spur? Would I need to do anything different if I chose to go for 3 fluorescent tubes instead of 6 bulbs?

Thanks. Moyzzie.

 

[Iggifer]

Taking them from the existing light is fine.

You only need to use 1mm cable not 1.5mm

I would try and arrange it so you go from one light to the next, to the next, rather than adding 2 branches from the existing light but you can do this if you need to

 

[winston1]

FCUs are not used on lighting circuits.

 

[RF Lighting]

They can be

 

[riveralt]

In my loft, there are lighting and socket cables, which converge in a grey plastic box, which I assume is a junction box (20cm x 20cm). From this box, there is a single cable to a switch and, from this switch, the cable continues to a single bulb in the middle of the narrow loft, where the circuit ends, so I assume this is a `spur`.

As others have said adding lights from the existing ceiling rose (light) is fine - However!!
You say that your loft has socket cables which enter a grey junction box and the light cable (assuming L/N/E) comes out of this to the switch and then (SL/N/E) to the light itself. No mention is made of the size of the mcb protecting the grey junction box. Lighting circuit protection is normally 6A, socket circuit protection is normally 16/20/32Amps depending on its design.

You will need to find out the size of the MCB protecting those socket cables and I suspect you will need to fuse down the lighting part of the circuit to 3/5Amp using a Fused Connection Unit.

If the switch you mention is a normal rocker then you can replace this with a switched FCU. If it is a pull switch then you will need to fit the FCU before the switch either as a replacement for the junction box or by breaking into the cable after the junction box. You will also need to ensure that the cable to the FCU matches the size of the socket cables normally 2.5mm ² T&E. Cable after the FCU can be 1mm² T&E.

 

[Iggifer]

If the junction box really does contain both lighting and socket circuit cables, whoever originally installed it would have to have been pretty special to not take his feed from a lighting circuit.

OP - find the breaker/fuse for the upstairs lighting and with the loft light on, turn it off/pull it out and if the loft light goes out - crack on with your plan.

If it doesn't, more investigation may be required.

 

[Moyzie]

Hi. Thanks to everyone who replied. I'm a bit confused after the responses. I opened up the grey box and the photo below shows what's inside. 5 cables with red/black/green wires enter the box with the single cable to the loft light switch exiting the box. Sorry if i sound stupid but I'm still not clear what is safe to do. Can anyone reassure me? Thanks.

 

[Iggifer]

well the feed to the loft light is a bit rough, you could tidy that back up, but other than that, just put the lid back on and take your new lights from the existing. Easiest and most logical way (unless you want to switch them separately)

 

[deadshort]

it's easier to take the additional lights from the existing light fitting use a good quality batten lamp holder with loop in terminals. If you don't known enough about electrics don't try to add wiring to that junction box.

Regards,

DS