Best practice for attic light installation

jodaw

Just installing some storage in the attic at the moment and want to install a ceiling light.

My lighting circuit is looped at the switch.

I am looked for some info on what would be considered the better of these two approaches.

1. Locate the permanent live coming into/going out from the bedroom switch in the attic. Split the cable and install a junction box on joist.
Run new cable to switch position on floor of attic and then onto the ceiling light fitting.

2. Do not part the cable in the attic and no junction box. Instead fish a new cable from the attic to the switch. And from here to the new switch. So i would then have three cable connected to the switch terminals.

What would be the better of these two? Or should i go a different route?

John Electrician33

No 2

Luckysasha

No junction boxes please!!!! If you have the live looped through your switches fish a new 1.5 mm2 brown down to the switch. Run this to your new switch in the attic or better still what I do is put a double switch in the bedroom altogether and label one as the attic lights. That way your just pulling a new 1.5mm2 brown to your light and a 1.5mm2 blue and earth to the nearest ceiling rose.

jodaw

Luckysasha wrote: »

No junction boxes please!!!! If you have the live looped through your switches fish a new 1.5 mm2 brown down to the switch. Run this to your new switch in the attic or better still what I do is put a double switch in the bedroom altogether and label one as the attic lights. That way your just pulling a new 1.5mm2 brown to your light and a 1.5mm2 blue and earth to the nearest ceiling rose.

Only thing about a switch in the bedroom would be that maybe the attic light might be left on by mistake. Still it would prevent messing about with switches in the attic.

So could i just run a length of twin and earth from double switch in bedroom direct to lampholder in attic and earth at the switch itself?

Luckysasha

No a T&E is no use as you don't have a neutral at the switch. You need to pick up a neutral at the nearest ceiling rose in any of the rooms. Handiest way I find as sometimes it can be tight to get a phase and earth down to the existing switch is a single from existing switch to new switch. If you are worried about the lights in the attic being left on what I do is put the switch in the room wher the trap door is. That way you can put the lights off before you close the trapdoor.

jodaw

Luckysasha wrote: »

No a T&E is no use as you don't have a neutral at the switch. You need to pick up a neutral at the nearest ceiling rose in any of the rooms. Handiest way I find as sometimes it can be tight to get a phase and earth down to the existing switch is a single from existing switch to new switch. If you are worried about the lights in the attic being left on what I do is put the switch in the room wher the trap door is. That way you can put the lights off before you close the trapdoor.

I am getting more confused now rather than the picture becoming clearer

I have a lot on T&E on hand that needs using and no single core cable. I could strip the outer insulation on the T&E and take the length of thinner ground that i require, which would be easier to fish to the switch.

I am uncertain which route i will take so I will explain my thoughts on each option and maybe someone can point out the errors of my ways.

1. No switch in attic - Since my lighting circuits are all looped at the switch rather than the ceiling rose, i take it i would be good just to run a T&E from the switch direct to the lampholder. I have neutral, earth and live at the switch? I am a little confused since post above recommended neutral and earth at ceiling rose and live from bedroom switch.

2. Switch in attic - Single one way switch in attic surface mounted on the floor with plastic backbox (no earth point)

My options here would be

- to fish a single core 1.5mm to the live at the bedroom switch, or a double insulated T&E, but only use the live core to connect to switch. I would feel more secure having a double insulated cable rather than a small single core live wire running through attic space.

- run another T&E from the out terminal on the switch to the live on the lampholder. Again only using the live core but using the T&E for additional protection of the cable.

- run a separate T&E from from neutral and earth terminals on the lampholder, to either the neutral and earth in the bedroom switch or to the neutral and earth on the ceiling rose rather than the the bedroom switch, which would be harder to get to with the need to fish two cables.

dingding

I would buy a few meters of 1.5 PVC/PVC in brown and the same in blue with some earth wire.

The T+E is not the way to go for this job because if you take off the grey covering you have no mechanical protection and if you leave it on, it is two clumsy.

jodaw

So maybe some of this from bedroom switch to attic switch and onwards to light fitting


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then from light fitting back to either ceiling rose or bedroom switch


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Having trouble sourcing these cables in anything but larger quantity. Any recommendations where i could pick up some smaller qty's at a reasonable price?

Luckysasha

The single 1.5mm2 brown and blue I recommended is double insulated, it has a grey outer sheath just like your T&E and a coloured inner sheet so it's safe to use don't worry. In fact if your saying that the lives are looped through the switches this is what would have been used. So just bite the bullet spend the few quid go in to any electrical wholesallers and ask for 1.5mm2 brown PVC / PVC and blue 1.5mm2 PVC / PVC 1.5mm2 earth a one gang one way switch and plastic surface box and whatever light fitting you want and just do the job

danjo-xx

jodaw wrote: »

Any recommendations where i could pick up some smaller qty's at a reasonable price?

Woodies etc sell it by the meter.

dingding

Some electrical wholesalers will sell by the meter. Also should be cheaper than DIY stores such as woodies and Homebase etc.

Jimmy_M

If there's a kellehers near you they sell most cable by the metre. Always cheaper than woodies bnq in my experience so far.