Dropping a length of lighting cable into a circuit.

[Benchwayze]

In my loft there is a length of cable that goes across the floor, from one bedroom rose to another. I know the pesky thing is there, but I regularly foul it when I am up there. To get rid of this trip hazard, I want to cut the cable and drop in a spare length, (About 2.5 metres) so I can raise it overhead in the roof 'A' frame. I plan to 'cable-clip' the new length up one side of the 'A' frame, and down the other, joining each end to one of the new ends where I have cut through. I hope someone can envisage this.

I think it's possible, but I need to know what to use to connect the new length of cable, safely, between the two ends of the existing cable, after I've cut through it. (Yes I am isolating the circuits first. ) I hope someone who knows can envisage what I mean. Can someone please advise as to whether or not I can use two of those circular, Bakelite junction boxes to make safe connections?

(Or would some of that nylon/plastic strip with the screw connectors suffice, if it is insulated afterwards? I doubt it of course, as that seems like a lash-up.)

I'm not a qualified sparky, but I know when a connection is good, and I know which is pos, neg and earth.,
I also believe I should put green and yellow sheathing on the earth wires.

Thanks in Anticipation

 

[Lons]

In my loft there is a length of cable that goes across the floor, from one bedroom rose to another. I know the pesky thing is there, but I regularly foul it when I am up there. To get rid of this trip hazard, I want to cut the cable and drop in a spare length, (About 2.5 metres) so I can raise it overhead in the roof 'A' frame. I plan to 'cable-clip' the new length up one side of the 'A' frame, and down the other, joining each end to one of the new ends where I have cut through. I hope someone can envisage this.

I think it's possible, but I need to know what to use to connect the new length of cable, safely, between the two ends of the existing cable, after I've cut through it. (Yes I am isolating the circuits first. ) I hope someone who knows can envisage what I mean. Can someone please advise as to whether or not I can use two of those circular, Bakelite junction boxes to make safe connections?

(Or would some of that nylon/plastic strip with the screw connectors suffice, if it is insulated afterwards? I doubt it of course, as that seems like a lash-up.)

I'm not a qualified sparky, but I know when a connection is good, and I know which is pos, neg and earth.,
I also believe I should put green and yellow sheathing on the earth wires.

Thanks in Anticipation

I would always use junction boxes John, just make sure you get the correct amp boxes (eg dont use 5 amp meant for light circuits on a 2.5mm ring circuit). i wouls always use the earth sheathing as well btw.

They are dirt cheap, I've just bought some HD ones for 84p from screfix.

cheers

Bob

 

[AndyT]

There's a possibly easier option - get a sufficiently long piece of cable to cover the whole distance between the ceiling roses and use it to completely replace what is there now. It will probably cost less for the extra cable than connectors would, and there will be no additional joints to fail.

 

[Tinbasher]

Andys way would be my ideal but Lon's is next best.

 

[Benchwayze]

Thanks Gents. (Lons, Andy, Basher)

I have a suspicion though I should get the work examined afterwards, or does that just apply to installing new lights, fitments and complete circuits? :duno:

Andy, your way is ideal I agree, but to do it I would have to crawl under the eaves, and wade through 12" deep insulation, plus the problem of working in a cramped space. Even a fit young sparky would be cursing.

So Andy, whilst I know you have my best interests at heart; I'll go for dropping in a new length. I can work sitting down then... :wink:
Screwfix here I come.

PS. I might have 90% of a 50m drum of lighting cable going begging afterwards BTW. :mrgreen:

 

[Peter T]

Thanks Gents. (Lons, Andy, Basher)

I have a suspicion though I should get the work examined afterwards, or does that just apply to installing new lights, fitments and complete circuits? :duno:

Andy, your way is ideal I agree, but to do it I would have to crawl under the eaves, and wade through 12" deep insulation, plus the problem of working in a cramped space. Even a fit young sparky would be cursing.

So Andy, whilst I know you have my best interests at heart; I'll go for dropping in a new length. I can work sitting down then... :wink:
Screwfix here I come.

PS. I might have 90% of a 50m drum of lighting cable going begging afterwards BTW. :mrgreen:

Rather than struggling to do it near the eaves, could you not take down the ceiling rose, feed the cable up through the hole, and then connect the new cable to the rose?

 

[Benchwayze]

Thanks Gents. (Lons, Andy, Basher)

I have a suspicion though I should get the work examined afterwards, or does that just apply to installing new lights, fitments and complete circuits? :duno:

Andy, your way is ideal I agree, but to do it I would have to crawl under the eaves, and wade through 12" deep insulation, plus the problem of working in a cramped space. Even a fit young sparky would be cursing.

So Andy, whilst I know you have my best interests at heart; I'll go for dropping in a new length. I can work sitting down then... :wink:
Screwfix here I come.

PS. I might have 90% of a 50m drum of lighting cable going begging afterwards BTW. :mrgreen:

Rather than struggling to do it near the eaves, could you not take down the ceiling rose, feed the cable up through the hole, and then connect the new cable to the rose?

Peter,

And connect the respective ends in the two bedrooms you mean?
That did occur to me. I thought of getting Number One Son to go in the loft and pull the cable through from bedroom one, and feed it down into bedroom two! The problem is getting the connections in the roses correct. I believe they are connected in a parallel circuit, to other roses? I think that's where I might make a wrong connection.

Far safer for me to drop in the length of cable. I have only to connect like to like, once in each box.

 

[Lons]

I have a suspicion though I should get the work examined afterwards, or does that just apply to installing new lights, fitments and complete circuits? :duno:

Haven't got the regs in front of me John but it isn't a notifiable alteration as long as you consider yourself to be competant (which I'm sure you are).

It isn't a new circuit and not in one of the controlled areas such as kitchens and bathrooms. just make sure the junc boxes are screwed in a safe place and all connections are "like for like" and tight.

One thing comes to mind though. If older wiring, you might be using different colours. In that case there are supposed to be notices posted on the consumer unit. (personally, I'd put labels on the junction boxes.

Bob

 

[Lons]

And connect the respective ends in the two bedrooms you mean?
That did occur to me. I thought of getting Number One Son to go in the loft and pull the cable through from bedroom one, and feed it down into bedroom two! The problem is getting the connections in the roses correct. I believe they are connected in a parallel circuit, to other roses? I think that's where I might make a wrong connection.

Far safer for me to drop in the length of cable. I have only to connect like to like, once in each box.

Could also be a ring circuit. You can tell by looking inside the rose.

Remember that there will be a permanent live feed in this case which connects to the feed down to the switch and back to the rose as switched live. Neutral is just connected through. There may also be another wire if any 2 way switching.

I have a leaflet somewhere we used to teach the basics at college. If I can find it I could scan if of any use but also loads of info on the net I should think.

Theres no doubt that the junc box method is probably quickest and perfectly safe and acceptable but a full length of wire is even better. personally I'd be quite happy to use boxes if access was a problem.

Bob

 

[Benchwayze]

Thanks Bob.

Yes, I am quite able to do this 'like-to-like' connection, and the wiring isn't quite old enough to have red, black and green sheathing. (I am old enough to remember it though!) :mrgreen: House was built in 1971.

There's a copper earthing wire in the cable, but there is no earth sheathing except where I have installed it over the years, as I replaced pendants. (They become too short after replacing lamp-holders more than a few times!) So I will have to add green and yellow sheathing in the junction boxes.

I found this online:

http://www.diydata.com/electrics/juncti ... on-box.php

It looks right and also easy enough, if I get the right boxes. I am struggling a bit with matching the cable size, but I do have a short length in the shop, that I can take for comparison. Fortunately Screwfix have a depot about ten minutes away from me. :wink:

Thanks again Bob.

 

[RogerS]

.....

I would always use junction boxes John, j.....

Bob

As it is lighting, isn;t that overkill? Wouldn't one of these be easier and neater ?

Or even the clear plastic box above

http://www.tlc-direct.co.uk/Main_Index/ ... index.html

 

[monkeybiter]

+1 for junction boxes. Secure, neat, with cable clips there's no need for strain relief.

 

[Lons]

Hi John

If lighting wire then it will be either 1mm or 1.5mm. It will be stamped / impressed into the outer sheath. If in doubt then I would put in 1.5 rather than undersize it though it nreally isn't critical.
You should be able to buy by the metre from any of the sheds or DIY stores if you don't want a reel.

Earth sheathing can be green/ white or more commonly just green.

I tried to access the Screwfix site but it's down. From memory, the 5 amp (3 or 4 terminal) were around 60p each and that's what you need for a lighting circuit.

I have a few - pity you aren't nearer.

Bob

 

[flying haggis]

Hi Benchwayze

your profile doesnt say where you are but if you are near me in norfolk I have reels of cable in the garage that you would be welcome to take and use what you needed

if it was me I would replace the length of cable with a longer one if poss, but as the cut and join is probably easier there is no problems using junc boxes, and if you ever need to add a light in the loft the feed is already there in the junc box! I always use the MK one as the internal connections are individual and therefore obvious

http://www.tlc-direct.co.uk/Products/MK1131.html

and for lighting circuit wiring diagram see here

http://www.diynot.com/forums/viewtopic.php?t=37582

Lons Earth sleeving is now green/yellow

 

[Benchwayze]

Hi Benchwayze

your profile doesnt say where you are but if you are near me in norfolk I have reels of cable in the garage that you would be welcome to take and use what you needed

if it was me I would replace the length of cable with a longer one if poss, but as the cut and join is probably easier there is no problems using junc boxes, and if you ever need to add a light in the loft the feed is already there in the junc box! I always use the MK one as the internal connections are individual and therefore obvious

http://www.tlc-direct.co.uk/Products/MK1131.html

and for lighting circuit wiring diagram see here

http://www.diynot.com/forums/viewtopic.php?t=37582

Lons Earth sleeving is now green/yellow

Thanks Haggis...

I am in Brum. (Ref. my avatar... I guess you aren't familiar with the Bull in Birmingham's Bullring. (There's plenty of Bull in Brum, btw!) :mrgreen:

Thanks for the offer of course. I think I will spend some time in Norfolk with my paints, but it's going to be sometime before I can. I did think about a light in the loft, as I use a 'wandering-lead' at the moment. As you say, the junction box would be an ideal pick-up point. Thanks for the offer. It's appreciated, regardless.

Thanks for that link, showing the Junction-box set-up too. That's a useful item, as is the Forum it came from.
Obliged.

 

[Lons]

Lons Earth sleeving is now green/yellow

Thanks Haggis, I knew that but didn't phrase it well which was silly on my part as we never know who's reading the posts and I wouldn't want to mislead a novice.

Comment wasn't meant to advise Benchwayze what to buy - he doesn't need the advice - what I was trying to say was that green is what will be encountered most.

I'm actually still using green on my own stuff as I have the remainder of a reel left and after all everybody and his dog associates green with earth. :lol:
I don't remember the regs stipulating a date when green couldn't be used any more, just that is was phasing in the new colours but I'm not going to chuck it whatever. Too much of a cheapskate :wink:

Bob

 

[Pond]

John,

You may have done this already, but if you haven't it is worth checking before you buy the cable whether the existing cable is 2 or 3 core plus earth. If it is a link circuit it may well be 3 plus earth (live, common live, neutral and earth).

Also use the same size cable as existing, or larger; never smaller! Check the fuse/ trip/ breaker amperage on the distribution board. Houses of the age of yours commonly had just one lighting circuit for each floor and were often 10 amp, not the modern 6.
1mm2 cable is not necessarily large enough for a 10 amp fuse (cable sizing is not at all straightforward).

HTH

 

[Benchwayze]

Thanks Pond.

I have checked and the equivalent of 1.5mm is what is there, so I am going shopping tomorrow!
Thanks again.

 

[Phil Pascoe]

A guy doing some work for me told me that many people use 1.5mm for the radial, and 1mm for individual lights and switch drops - this seems to make sense - up rate the supply slightly, keep the bulk of cable down in the switches and fittings, and make it a little more obvious what's what when there are four cables hanging out of a ceiling rose.

 

[Benchwayze]

Thanks Phil

My theoretical 'expertise' with electrics stopped at EMF, Back-EMF' and Faraday's Cage!

I am also more conversant with the DC variety of electricity, having worked on torpedoes and asdic circuits. But that was long, long ago, in a time-sphere far away! :lol:

Cheers..