upstairs lighting re-route of cable

[RonO]

I have to think about re-routing the cable from the CU to the loft for the upstairs lighting circuit as currently the cable comes down through the one place I wish to put a door downstairs.

rather than chisel away up through the two floors to relay the cable, my preferred (easiest) route would be to use conduit to go diagnally up the stairs (under stairs) through a wall into the ceiling space in the corner of the kitchen and follow the central heating pipes up in to the airing cupboard then up into the roof.

Questions:

1. is it permissable to run conduit for this purpose along side heating pipework?
2. Should I use plastic or metal pipe for the conduit

 

[elrobbo82]

as long as the cable is concealed in the conduit and surface mounted i wouldn't envisage a problem with this. i would use pvc conduit as this would not have to be earthed and is considerably cheaper and easier to install.

 

[ericmark]

In theory central heating pipes should be no more than 70 degrees and so if you use 624B Twin & Earth LSZH Cable 300/500V BS7211 which is rated at 90 degrees (not 624Y Twin & Earth PVC Cable BS6004 A05VVH4-U) then it with such a small current be OK.

You are not permitted to run cables buried in the wall diagonal but you can if surface mounted. So yes as long as the route is visible so in the future no one is likely to hammer a nail through the cable it would be OK.

The other option may be to go outside with an armoured cable or other suitable protected cable.

As to plastic v metal the PVC may not take the heat so although easier in that you don't need to earth it may be better with metal which will better stand the heat but will need earthing.

Guardian Ali-Tube/LSZH Cable BS8436 600/1000V is also rated at 90 degrees and may be an option but the main problem is to find where one can buy a small quantity as it tends to be only sold by the role.

 

[elrobbo82]

i wouldn't have thought that the heat from the central heating pipes would be too much of a problem unless the conduit was touching the pipes. if as ericmark says that the central heating pipes can get up to 70 degrees (im assuming celsius) then check for ambient temp using a thermometer. if the temp is below 60 degrees celsius or 140 degrees Fahrenheit then pvc conduit should be fine. just remember to derate the cable.
p.s.
meant to say derate if needed, sorry

 

[RonO]

Elrobbo32: what do you mean by "derate the cable" I was going to use the existing cable because this would be a shorter run, the cable was only laid 3yrs ago and is the thicker 1.5mm lighting cable

 

[elrobbo82]

if you a running a cable through an area with a high ambient temp the the current carrying capacity will drop. this can be a significant decrease depending on the temp. i don't think it will be a problem in this instance as i don't envisage the temp to be as high as to alter the cable size. i don't have my onsite guide to hand but i think max current carrying capacity for 1.5mm t+e is about 18A with no derating factors. im sure some one else will post with the correct current carrying capacities and the correct derating factors.

 

[EFLImpudence]

You do not need to worry about the rating for a lighting circuit as the cable is rated for far more than twice the 6A of the circuit.

 

[starspark]

if as ericmark says that the central heating pipes can get up to 70 degrees (im assuming celsius)

What else would he mean fahrenheit!!

 

[elrobbo82]

starspark
have you not got any input or do you just bully new members?

 

[starspark]

elrobbo not need to take it personally!
i have made an input and that was hardly bullying!!
maybe you should stick to the painting forum and copy and pasting other peoples answers if your having trouble with this forum!!

 

[elrobbo82]

its hardly input. its not constructive at all. i'm surprised that you didn't pick up that i said derate the cable and not apply the derating factors. i left this open to you to jump on but obviously over estimated your ability. maybe you could try to answer a question instead of just causing arguments.

 

[starspark]

i'm surprised that you didn't pick up that i said derate the cable and not apply the derating factors. i left this open to you to jump on but obviously over estimated your ability.

bit sad that aint it??
You edited it so i thought i would cut you some slack as im a nice guy your just immune to my charms i think!!

And i answer many questions, i dont however pursue animals in arguements not sure where your going with that one??

 

[elrobbo82]

confused!!! animals!!! more constructive input i see!!!

 

[starspark]

correct im trying to help you make your posts clearer to members so i would say thats very constructive.Im trying to help you elrobbo if you feel im being critical then perhaps a forum is not for you.

 

[elrobbo82]

look i'll be the bigger man here and walk away from a pointless debate that isn't getting anybody any answers. lets just go back to the original post and let you put you're point of view across as you must have some actual input on the post hence why you entered onto this post.