routing lighting cables

[nabby68]

hi everyone, my query is that i am currently installing downlighters (mains operated) in my bedroom and have decided on five in a sort of "cross" formation with the exsisting ceiling rose being included and converted to a downlighter. my question is, how hard or easy is it to feed the cables from the ceiling rose to each of the holes i have cut for the downlighters? any tips or tricks would be appreciated. cheers

 

[andy]

hi everyone, my query is that i am currently installing downlighters (mains operated) in my bedroom and have decided on five in a sort of "cross" formation with the exsisting ceiling rose being included and converted to a downlighter. my question is, how hard or easy is it to feed the cables from the ceiling rose to each of the holes i have cut for the downlighters? any tips or tricks would be appreciated. cheers

you can feed them down the gaps in the joists, but youll also have to drill holes in them to go the other way. all of this will require access from above so youll have to take some floorboards up

 

[nabby68]

hi, thanks for that andrew, but accessing from above is a no, no, as i live in a groundfloor flat. how wide apart should my joists be? and further, how can i get past the joists with not being able to acess them from above therefore unable to drill through them?

 

[andy]

hi, thanks for that andrew, but accessing from above is a no, no, as i live in a groundfloor flat. how wide apart should my joists be?

not easy. youll have to either take large amount of ceiling down so get wires thru

OR

find which way the joists go. try and dog the cables along from light fitting to wall. knock up there to bring wire down, along top of ceiling then along to next light. youll probably have to put coving up to hide the wires

NOTE: only wires connecting lights shown. not switch wire or feed, since they should already be at the first light your wiring them from

heres a diagram. quickly drawn so not the best, but you should get the idea

OR

if your on good terms with people above, and there re-decorating their room (very unlikely), ask if you can take some boards up

 

[nabby68]

thanks again andrew for the reply and diagram. what are your views on coming under the joists by drilling the ceiling and then chiselling out enough of the joist to fit the cable in then replacing the off-cut into the joist then patching up the ceiling.

 

[andy]

thanks again andrew for the reply and diagram. what are your views on coming under the joists by drilling the ceiling and then chiselling out enough of the joist to fit the cable in then replacing the off-cut into the joist then patching up the ceiling.

the cables need to be 50mm into the joist. for this, you should drill them, since if you cut it to that depth you will severly weaken them. but to do that youll have to take a area down big enough to get a drill in to drill them. if you lucky, there should already be holes from where the existing cables go thru. if you find these, then you can feed your cables thru the same hole if its big enough

 

[mapj1]

If you do notch the joists, and its not good practice, but the risks from carpet nails are less from below than from above! you could go down the 'or equivalent protection' rute of a steel plate to cover where the wire goes through.
I have solved this problem in the past using a long (~3 ft) drill bit to drill the joist centre, slightly skew, but it means feeding the bit in through an additional hole, and lots of cunning with coathangers is needed, and it still means a lot of patching up.
Is surface trunking, or a false ceiling made of plasterboard on battens an option?

 

[nabby68]

thanks mike. false ceiling not an option as i dont really want to lower is anymore as it is low enough now and trunking would not be cosmetically pleasing

 

[user56565]

unfortunately nabby68, you're in a difficult position and it will require some messy messy work. you have 3 options:

1) ask the guy upstairs if they'll let you get access. it's not an unreasonable request, and would only take a day. then route cables as normal practice and drill through joists.

2) route cables as normal practice and drill through joists, accessing only from below. you will have to pull down large amounts of your ceiling (little holes will make your life difficult and probably won't be sufficient- cables need clipping to joists at regular intervals, and you'll need to also get space for a hammer etc..). it's likely you'll end up pulling down a fair amount, and it may be easier to pull down the whole ceiling. replacing the ceiling - get plasterboard, screw on, then get a plasterer in to do the skimming..

3) follow andrew2022's option as his diagram. you'll need a lot of space once again to get your hammer in, so it's not a simple case of patching up. however drilling wouldn't be necessary. if you do this, you'll have to make sure the cable in the wall is in the 'recommended zones'. ask us if you're not sure what this is...


if you drill into joists, you must be aware of building regs as to where you can drill holes (you can't just drill a hole wherever you please), ask for more info if you're taking this option. don't notch, it weakens the joists much much more than a hole. i always clip cables against joists, however some here may take the view that's unneccessary, and you could just let your ceiling support the cables. if you do this, you then wouldn't need to make big holes in your ceiling for hammer etc..

is this ok??

ps are you aware of part p?? //www.diynot.com/forums/viewtopic.php?t=27936
its up to you whether you bother, but you should know.

 

[breezer]

couple of things

floor ceiling between you and upstairs probably has insulation / sound proof material in between the joists (place i live in did, and i only found out when i lifted a floor board, and i was upstairs)

The fact that you do not like the look of trunking is just too bad, its not that bad, easy to install, and looks like your only viable option, unless you go for uplights

 

[user56565]

ahh yes, although not that common, some flats are separated by insulation/soundproofing material. have a quick check on this first, because it will make it almost impossible to put all the cables above your ceiling. this may also stop you from putting the downlighters in (heat build up)

 

[andy]

ahh yes, although not that common, some flats are separated by insulation/soundproofing material. have a quick check on this first, because it will make it almost impossible to put all the cables above your ceiling. this may also stop you from putting the downlighters in (heat build up)

been on some house re-wires earlier this year. just about every house had sound proof stuff between floors, even in houses. however, this didnt cause a problem whilst tryin to dog cables accross to the side

 

[user56565]

if he's accessing from below however, the insulation may fall out. he'd have to make sure the cables are going to rest above the insulation and not get surrounded by it. finally the lights themselves may cause a problem with the heat generated.

 

[supersparks]

another quick point

depends on wheather flats are purpose built or converted but, i have encountered in the past....

concrete ceilings battoned off by about half inch for cables.

very common to find double or triple skin plasterboard ceilings

hell i even know one place which is double skin ceiling, 6 x 2 joists
then 6x2 joists running across them, both cavitys filled with different types of insulation, on top of which is floorboard, half inch plasterboard, then chipboard floating floor.

now, have fun with heat in there!

snd andrew, a fan of dogging ay

 

[andy]

snd andrew, a fan of dogging ay