New Loft light - need help on final hurdle!

[oakc]

Hi guys,

i hope someone can help - i'm fairly new to electrics but understand the basics and have done ALOT of reading/researching.

i have fitted a fluorescent light up in the loft and the plan was/is to change the landing switch to a 2 gang switch one still working the landing light and the other working the loft light.

i started following this guide (its really descriptive!)
http://www.diyfixit.co.uk/electrics/installing-a-fluorescent-tube-fitting-and-switch.html

however I'm a little unsure on determining which is the "live feed" to cut.

the most convenient one is the landing light which is a single spotlight however when checking the wiring this is what i've got.

their is a choc-block/terminal block with insulation tape on which has:

Cable From spotlight - brown & blue cable
Cable From Landing Switch - Red, Black, Earth (Red in L1, Black (with red tape on) in L2)
Cable From i'm assuming it's either the feed or downstairs switch as it's 2 way - Red, Black, Earth
Cable From Switch - single red cable (in Com)

in each terminal:
term1
landing switch cable (black), live feed or downstairs switch cable (black), spotlight (blue)
term2
all earth cables
term3
all red/live cables (except single red cable)
term4
spotlight cable (brown), single red cable from landing switch (wired in com)

i can attach pictures if it makes it easier but from what i've described will that cable be the feed or the cable connecting to the downstairs switch? (i think because its 2 way its throwing me)

can i cut that cable n add the junction box new switch n fluorescent lght as per tutorial, i did try taking apart term block and wiring to the junc box along with new switch and light but now both switch control both lights ... well actually even the downstairs switch controls both lights!

so close but so far!! any help would massively be appreciated!! if i've done something drastically wrong please go easy on me n just let me know what i did wrong first attempt of adding new light to lighting circuit

 

[EFLImpudence]

I'm a little confused.

Cable From spotlight - brown & blue cable
Cable From Landing Switch - Red, Black, Earth (Red in L1, Black (with red tape on) in L2)
Cable From i'm assuming it's either the feed or downstairs switch as it's 2 way - Red, Black, Earth
Cable From Switch - single red cable (in Com)

Which switch is this (second one)?

Pictures will help.

 

[oakc]

Sorry basically im tlking about the same switch on landing, got two grey cables coming from landing switch one is t&e (red black, earth) the other just has a single red cable. Will get some pics if this still doesnt make sense (will be 2moz though - wife telling me to stop for today lol)

 

[PrenticeBoyofDerry]

You really don't want to be cutting into cables on a cable that you cannot prove is dead!
By your description the single red and the twin and earth (red, black, CPC/earth) sounds like the two way arrangement, that would still mean you require a neutral for the new light to work.
The neutral will likely be looped in at the lights rather than the switches.
So you will require the permanent live from the switch, this can be linked across a two gang switch and then taken to the light, also you will require to take a CPC/earth from switch to fitting, then you will need to find and connect a neutral.
I suggest you purchase a multi-meter if you do not already have one, this will help you test for continuity and voltage, the other thing to consider if using the lighting switch on the landing, if you bury the cable within the wall less than 50mm and without mechanical protection, then you will then require RCD protection, if this does not already exists on the circuit.

Personally I would have the switch in the loft near the loft hatch, this will mean that you are not accidentally turning light on at landing and leaving energised without knowing, and you could also then have the cables clipped or in containment such as trunking, instead of buried within walls, therefore you would not then require the added protection of the RCDs if they do not already exist on the circuit!

 

[oakc]

Oh its just that tutorial say to cut into existing light live feed though to add junction box :-S so are you saying could do it without juction box? also luckily existing swich cable has cable proctection running down to switch and enough room to run cable down to switch (for the loft switch).

So from what ur sayin wud i still run t&e cable down to the switch? Thanks for the replies!

 

[PrenticeBoyofDerry]

Oh its just that tutorial say to cut into existing light live feed though to add junction box :-S

I would try to avoid cutting into cables that you cannot prove are dead and I would also try to avoid the use of unnecessary junction boxes.

so are you saying could do it without juction box?

It could be, you need to determine which cable core is the permanent live at the landing switch, I would guess (and it is a guess, you would need to prove this) that it is the single red. This can then be linked across to the switch for loft light at com, then from L1 you can then take this to the live side of loft light, also run the circuit protective conductor (CPC/earth) from the switch to the light, you then need to locate the neutral conductor, this is likely to be looped in at the light fittings, again this can be taken from that point directly to the neutral side of loft light, therefore no joints or junctions required, but the one you have found needs doing correctly, ideally with a maintenance free box rather then a standard junction box and definitely not in connector and wrapped up in tape!

also luckily existing swich cable has cable proctection running down to switch and enough room to run cable down to switch (for the loft switch).

Metal capping is not deemed a suitable gauge to accepted as mechanical protection, you would require a gauge of 3mm, or metallic conduit or earth shielded cable. or RCD protection. If you cannot bury greater than 50mm. (there are regulations that also concern maximum depth of chases within walls, this often means that the 50mm cannot be achieved)

So from what ur sayin wud i still run t&e cable down to the switch? Thanks for the replies!

You could but one of the twin cores would not be required, as you only
need a live line and a CPC, the neutral can be linked between lights.

There are single core and earth cables available on the market, any good electrical wholesaler will cut you some to length required.

 

[oakc]

Metal capping is not deemed a suitable gauge to accepted as mechanical protection, you would require a gauge of 3mm, or metallic conduit or earth shielded cable. or RCD protection.

i believe it's metal conduit - i will take a photo and upload to make sure also our whole house has spotlights and looking at every spotlight has a connector/terminal block with taping wrapped round it!?! :-S

i'm suprised because the guy who i bought the house off (who is now my next door neighbour) said when he renovated the house he had electrician in to sort out all the new lights (spotlights) so would of thought it would of been to proper standards!

thank you so much for this - makes so much more sense. a few rookie questions though

1. being a fluorescent light doesn't affect anything in regards to wiring does it?
2. because the spotlight has a connector/term block will that be the point where it is looping for the neutral or will it physically be in the light itself (haven't checked under the hood where the two cables are coming out)
3. the red tape around existing black cable going into L1 looks like it's connected to all the other neutrals (light, other cable (feed/downstairs switch) i thought the red tape is to indicate the neutral cable is being used for live?

thank you so much for this i got myself in a knot with it, second guessing myself and things i read contradicting stuff but this makes so much sense!!!!!!!

 

[oakc]

would this multimeter be ok to do the testing?
http://www.screwfix.com/p/lap-mas830b-digital-multimeter-600v/75337

i assume you turn off lights at consumer unit and connect red cable to multimeter?

also trying to find single core + earth cable at general stores (screwfix, wickes etc) but none have it listed :-S will find a decent local electrical wholesaler near by. also do they do single neutral cable - assume got to sleeve them with correct colour?

thanks again!

 

[PrenticeBoyofDerry]

i believe it's metal conduit - i will take a photo and upload to make sure

Metal conduit would be okay, but you may struggle getting additional cable through them without causing damage to exist or new cables

also our whole house has spotlights and looking at every spotlight has a connector/terminal block with taping wrapped round it!?! :-S

Then it has been done by a numpty then, the connectors should be enclosed within an insulated enclosure not taped up.

i'm suprised because the guy who i bought the house off (who is now my next door neighbour) said when he renovated the house he had electrician in to sort out all the new lights (spotlights) so would of thought it would of been to proper standards!

How long ago was this done, was the alleged electrician registered? As what has been done by your description is the work of a cowboy!

thank you so much for this - makes so much more sense.

Happy to help, as I said yu will need to do some investigation and having a test meter available for use is a very necessary tool.

a few rookie questions though

Will try my best to answer them for you.

1. being a fluorescent light doesn't affect anything in regards to wiring does it?

No

2. because the spotlight has a connector/term block will that be the point where it is looping for the neutral or will it physically be in the light itself (haven't checked under the hood where the two cables are coming out)

Finding the neutral will depend on how the circuit has been configured, but there will be a neutral at each light. Ideally you want to pick up the neutral before any switched string of lights.
There will likely be a connection/joint where supply, load and switching meet, I would pick up the neutral there if possible.

3. the red tape around existing black cable going into L1 looks like it's connected to all the other neutrals (light, other cable (feed/downstairs switch) i thought the red tape is to indicate the neutral cable is being used for live?

The red tape should be identifying the core as a live conductor, do not be fooled by thinking black cores a always neutral as they are not.

thank you so much for this i got myself in a knot with it, second guessing myself and things i read contradicting stuff but this makes so much sense!!!!!!!

There is a section in Wiki that may help you understand lighting circuits, they show the standard arrangements, but there are many ways to make lighting circuits work and they may not all be found in Wiki.
The important things to know are you require a live, neutral and CPC for the circuit to function, you require to route cables in the prescribed safe zones.

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• PrenticeBoyofDerry
• 16 Oct 2011
• 20

If you are installing new cables within walls, they will generally require RCD protection if they are buried less than 50mm (note regulation for chases in part A of building regs) or have mechanical protection (I would recommend at least 3mm gauge).
Also there is a requirement within Part P of building regs, that asked for reasonable precautions to be made in design, installation and use with regards to safety, in my eyes that would mean the work should be designed and installed in compliance to BS761 and inspection and testing of the work would be carried out during installation and on commision of the work, this would also be documented in the relevant model form, in your case a minor works certificate.
https://www.elecsa.co.uk/Documents/.../BS7671-Amd1-Minor-Works-Certificate-(1).aspx

 

[oakc]

It was around 5-6 years ago - i know he did cuz he sed the electrician said the cabling was such a mess so he "ripped it all out" and started again whatever that means, he is a builder so dont know if it was done as a favour but still standards!!

 

[PrenticeBoyofDerry]

would this multimeter be ok to do the testing?
http://www.screwfix.com/p/lap-mas830b-digital-multimeter-600v/75337[/QUOTE]
It would be okay for the testing of voltage and continuity.
There are a number of other tests that I as an electrician would need to perform, some can be performed and calculated by that meter, some cannot.

i assume you turn off lights at consumer unit and connect red cable to multimeter?

If you are testing for perm live, you would, identify circuit and isolate prior to removing any covers, remove covers, prove circuit is dead, then you could either by doing continuity tests identify the perm live, this can be done keep the circuit dead or you could test for voltage, this would require re-energising circuit and testing for AC voltage between Lives and CPC and switching the circuit on/off and then identifying the core that stays live regardless at what position the switch is in.

also trying to find single core + earth cable at general stores (screwfix, wickes etc) but none have it listed :-S will find a decent local electrical wholesaler near by.

Electrical wholesaler should stock, I would make few phone calls to confirm first, rather than making a journey out.

also do they do single neutral cable -

Yes

assume got to sleeve them with correct colour?

All cores need to be identified and doing this by colour is the preferred choice. The singles cores will require to be sheathed.

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• PrenticeBoyofDerry
• 4 Mar 2014
• 2

It is likely that the wholesalers will only have blue and brown cores

 

[PrenticeBoyofDerry]

It was around 5-6 years ago - i know he did cuz he sed the electrician said the cabling was such a mess so he "ripped it all out" and started again whatever that means, he is a builder so dont know if it was done as a favour but still standards!!

Builder=Cowboy Electrician
Did he look like this?

Picture Title

• PrenticeBoyofDerry
• 7 May 2013
• 8

If it was done in the last 5-6 years, I would expect a certificate to have been issued to state that it complies to BS7671, ask for this cert.
And check out if the the builder is registered on a scheme.
http://www.competentperson.co.uk/

 

[oakc]

Fantastic!! Will give this a go tomorrow and let you know how i get on! One last question (i promise!) These terminals/connectors that just have insulation tape wrapped round them is there anything like a sealed plastic casing i could get for the terminal or will i need to disconnect and re-wire every one to whatever i need/end up getting?

 

[PrenticeBoyofDerry]

This will depend on the size and nature of the connectors, any joints should be left accessible, if they are not they should be connected using a maintenance free method.

Links to suitable connectors:
http://www.screwfix.com/search.do?fh_search=choc+box

click flow
downlight junctions
maintenance free

 

[oakc]

you need to determine which cable core is the permanent live at the landing switch, I would guess (and it is a guess, you would need to prove this) that it is the single red. This can then be linked across to the switch for loft light at com, then from L1 you can then take this to the live side of loft light, also run the circuit protective conductor (CPC/earth) from the switch to the light, you then need to locate the neutral conductor, this is likely to be looped in at the light fittings, again this can be taken from that point directly to the neutral side of loft light.

This worked!! absolutely perfect! Perm Live was going into L1 so joined L1 with COM for loft switch.