Cables run in Cavity Walls

[Rodnay]

Any thoughts, Advice, Experience of running cables within cavity walls welcome please .

 

[Dan]

Hello Rodnay, welcome aboard. Enjoy the forum.

 

[Rodnay]

Thanks Dan

 

[SPARTYKUS]

Rodnay

Think it was done alot in
the past, come across a few, to be honest my heart sinks when I find it, cables chucked down from loft to ground floor, no support in the way of clips except the rough edge of the concrete block its draped over in the loft. Dirty great holes bashed from cavity to K/O box.


Bad bad bad

Would never do it!

 

[MarkieSparkie]

Hi, welcome to the forum.

 

[Geordie Spark]

Rodnay

Think it was done alot in
the past, come across a few, to be honest my heart sinks when I find it, cables chucked down from loft to ground floor, no support in the way of clips except the rough edge of the concrete block its draped over in the loft. Dirty great holes bashed from cavity to K/O box.


Bad bad bad

Would never do it!

Is this practice still permitted?

I don't think it is, but stand to be corrected.

 

[Sparky Ninja]

You'll need to make sure you consider the reference methods 100, 101, 102 and 103 and consider their impact on a conductors current-carrying capacity as illustrated in Table 4D5 in Appendix 4.

 

[kingeri]

I'd never run a cable in a wall cavity, it's just bad practice. Only exception for me would be going through
a cavity, e.g. outside light feed. If you do decide to do it, which I urge you not to, then I'd use something beefier than T&E too.

 

[the oracle]

Considered a bad practice these days, for several reasons;

a). the cable could get damaged by sharp edges etc within the cavity when pulling in.

b). the cavity could be filled with polystyrene insulation, which reacts with pvc

c). and most importantly, the cable can rest against the inner wall and the outer wall,
and therefore becomes a 'bridge' for moisture to run from the outer skin to the
inside skin, and thereby creating a damp patch on the inside of the wall.

This negates the whole purpose of having a cavity, hence you will find that building
inspectors on extensions and new builds will insist on having any cables they see
in a cavity removed and re-run . Short answer is, don't do it !

 

[telectrix]

last resort. only do it if there's no other way.

 

[ExArmy]

only thing i'd run in the cavity is tails when doing board changes and there are only 16mm tails.

 

[markc123]

b). the cavity could be filled with polystyrene insulation, which reacts with pvc

Slightly off-topic but you try tell that to static caravan manufacture's.....alot of modern caravans, most notibly Willbery have all the walls filled with polystyrene.....and the twin and earth literally just hidden in the middle of it.

Been to loads of caravans where people want single-sockets making into doubles.....chop out the other half with a stanley haha....and its completley chocker with polystyrene. Seriouslly no idea how they get away with such crap.

Came across one earlier with plug in light switches haha it made me laugh.....wired from the CU down to the switch....then they have chockyblocks with inbuilt plug-in-jobbys? Really not sure what they're called because hardly ever come across them but you'll probably no what i mean.....then they have the light switch wired and plugged-in in the drylining box. They're reasoning.................when the light switches become faulty (and by that wording they're obviouslly expecting them too) they send out a maintenance team, and because they're not qualified electricians they're only allowed to plug in equipment....thats the reason for them having their light switches and sockets wired in a plug-in system.

Lazy.

 

[telectrix]

cavity waal insulation does not react with the pvc of cables any more.

 

[Guest111]

cavity waal insulation does not react with the pvc of cables any more.

maybe not,but at leastI know why women develop damp patches now,and there was me thinking it was the effect I had on them lol.

 

[Engineer54]

maybe not,but at leastI know why women develop damp patches now,and there was me thinking it was the effect I had on them lol.

c). and most importantly, the cable can rest against the inner wall and the outer wall,
and therefore becomes a 'bridge' for moisture to run from the outer skin to the
inside skin, and thereby creating a damp patch on the inside of the wall.

You talking about this??

This is just another old wives tale, You could say the same about the metal ties the brickies use or the insulation materials that fills the void. The only time your going to get damp between walls, is when the outer wall (or small area of it) is no longer watertight, eg ...unfilled holes, pointing failure etc!!

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