What cable for second light?

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android75

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Hello
Have a 5ft double-strip LED light hard-wired into the loft by electrician on the main upstairs lighting ring with its own switch. Need to increase illumination so going to add a second light of similar design. What cable is best to use? I have some 2.5 sq. mm twin and earth, wondering if something smaller would be more suitable. Planning to add a simple junction box to split the power input coming from the switch to the existing light.
 
Probably best to read this:

BS 7671 Electrical Wiring Regulations Guide

A guide to answer your questions about the latest electrical wiring regulations and standards in the UK, including BS 7671 and a handy terminology checklist.
uk.rs-online.com uk.rs-online.com

Then this:
18th Edition Wiring Regulations

Or just get your electrician back to fit second light.

I've done my own (simple and legal) electrical jobs around the house and I always seem to attract those little electrons every time. Shocking experience!
 
Lighting cable is generally 1.5mm2 but if you've got some thicker stuff going spare then other than being a lot stiffer to work with, it'll be fine.
Yes, junction box to split the supply and you'll be fine. Just make sure you turn off the supply at the consumer unit and not just the light switch before you start - best to avoids those pesky electrons 😉
Oh, and I'd recommend a simple multimeter / tester. It doesn't have to be hundreds of quids worth, a £10 job is all you'd need for diy.
 
Perlogalism said:
Lighting cable is generally 1.5mm2 but if you've got some thicker stuff going spare then other than being a lot stiffer to work with, it'll be fine.
Yes, junction box to split the supply and you'll be fine. Just make sure you turn off the supply at the consumer unit and not just the light switch before you start - best to avoids those pesky electrons 😉
Oh, and I'd recommend a simple multimeter / tester. It doesn't have to be hundreds of quids worth, a £10 job is all you'd need for diy.
Click to expand...
Thank you for the helpful reply - this is what I needed. I suspected 1.5 sq mm was 'best' and you've confirmed it. I've got a multimeter and tester and will be sure to turn off at the consumer unit. Thanks for the advice!
 
Hello, for lighting you don't need anything more than 1mm sq twin and earth cable.
You could work out the current used by the lamp by using the formula, power of lamp in watts divided by the voltage at the lamp( best to measure it as it can vary) but generally it may be about 235v .
A 1mmsq cable is rated to carry 11A so I think you will be more than adequate for the single lamp.
Anymore questions please do shout up.
Or you could pm me for a chat if you want more info.
Cheers Maz.
 
Unless you’re supremely confident in your electrical prowess,get a sparky in and don’t mess 🙄
 
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maz1 said:
Hello, for lighting you don't need anything more than 1mm sq twin and earth cable.
You could work out the current used by the lamp by using the formula, power of lamp in watts divided by the voltage at the lamp( best to measure it as it can vary) but generally it may be about 235v .
A 1mmsq cable is rated to carry 11A so I think you will be more than adequate for the single lamp.
Anymore questions please do shout up.
Or you could pm me for a chat if you want more info.
Cheers Maz.
Click to expand...
Thanks for offer of help. I'll see what cable reels are in the box of bits 'n' bobs!
 
Splitting today power from the switch may not be good enough. You may have only a live and a switched live in the 2 core (anx earth) cable going to the switch. Far better just take a ² core and earth ( or twin and earth) from the L.N E terminals o btge existing light.
Size wise 1.0mm or 1.5mm woukd be fine.
 
android75 said:
Hello
Have a 5ft double-strip LED light hard-wired into the loft by electrician on the main upstairs lighting ring with its own switch. Need to increase illumination so going to add a second light of similar design. What cable is best to use? I have some 2.5 sq. mm twin and earth, wondering if something smaller would be more suitable. Planning to add a simple junction box to split the power input coming from the switch to the existing light.
Click to expand...
Where or how has the light been fitted, such that you need more light?
What wattage and colour temperature is it?

Iirc, I changed the original fluorescent tube fitting to a 50w Ansell Nouline 5ft batten, and positioned it high up centrally under the A-frame, instead of where the builder had spec’d the original on one side, part way down.
Even though the tube had long since been improved to a brighter and more natural white (4000ºK), the LED unit made a huge difference.
That might be all you need (or a 6ft version), better placed, than what you’re contemplating doing.
 
The light presently in there was newly-installed when house was rewired. It is LED and it is good, but the loft is big and I just need another LED baton to ensure I can see stuff when trawling through boxes of mementoes
 
If there is a convenient junction box connecting wiring to existing light, use it to connect wiring for new light in parallel with existing.
Sometimes, when existing wiring is buried under fibreglass the simplest solution is a new junction box on wiring convenient to the existing light, allowing cable for new light to be clipped to rafters without disturbance of the fibreglass insulation.
A minimal amount of slack in cable will allow a small screw type junction box to be connected without cutting existing cable. Just carefully remove sheath and bare conductors sufficient to make contact under the screws.
With position of new light determined and length of cable known, it is often easier to make the cable/light connection sitting at a table in daylight prior to installation and connection to power in the loft.
 
The wire thickness for a light hardly matters, but it should have an outer cover and be solid wire.
1. Turn the light on.
2. Turn the mains ring off at the box.
3. Check the light has gone off. Do a voltage check from all wires to earth to check safety and that no wire remains live- box wiring can be done wrong- which once could have killed me.
There are several ways of doing the next bit, mentioned by some posts above. Choice depends on how much cursing is required as wires slip out of a connector that is too small....
4. The existing light may have enough room/capability on its connector in which case you can go straight to step 6. If not, From the existing light, take exactly the same wires out, and put them in a proper junction box.
5. Remake the existing connections, junction box to existing light..
6. Duplicate the connections to the new light. If you have the wrong colours in your new wire, use some coloured insulating tape of the correct colour as an identifier around the wire at the new light end .
 
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