cable in cavity on external wall?Channel in brick or capping

[benjii19]

Hi all I've pulled down a chimney flue on an external wall and rebuilt in brick with a knockout box in situ for power. I've chipped off all the plaster from the wall as it looked shocking.

**My question is do I route the cable up to the knockout box on top of the brick work and plaster over (obviously using trunking) or can i feed the cable in the cavity?**

 

[ricicle]

Cables should not be run in cavities due to lack of proper support, possible inaccessible vermin damage and the tracking of damp across the cable from the outside to inside wall

 

[ban-all-sheds]

But they don't get supported if run internally in conduit....

Another cavity issue is that subsequent installation of CWI could damage the cable (depending on the type of insulation) and reduce its current-carrying capacity.

do I route the cable up to the knockout box on top of the brick work and plaster over (obviously using trunking)

If you want to run the cable in something use conduit, not trunking, and chase it into the wall or you'll need ludicrously thick plaster.

 

[sparkwright]

Do not use the cavity, it sounds like you wouldn't even need to.

Use plastic capping or oval conduit and plaster over. Oval conduit may prove to be thicker, so you may have to sink it in the brickwork slightly. Plasterers seem to prefer capping.

Make sure the cable run is in a safe zone ie directly vertical or horizontal with the socket accessory. This will reduce the risk of it ever getting drilled through etc.

Look up cable safe zones if in doubt.

 

[DJM]

What about running it in conduit in the cavity? The cable would be:
- Protected from vermin,
- supported,
- can still be pulled through if cable needs replacing,
- no channelling in wall required,
- proteced from EPS
- provided with an air gap to reduce potential cable overheating if CWI installed.

I would add a smiley for tounge in cheek but can't see one, but even though it's a cheeky idea it does cover a lot of the bases

 

[planemad]

If you are going to go to that much trouble you may as well find another cable route.

 

[SUNRAY]

There is a recent housing development where they built the internal thermal block walls, then ran plastic conduit on the outside for all the services [electric, phone, music system, cat5, central heating, etc] then insulated and the outer skin built.

Made it very neat and tidy and to a good standard so anything could be replaced when required, and a number of spare positions supplied too. All very impressive and all in the cavity.

 

[benjii19]

Looks like I should use protective channeling then which I believe is about 8mm deep and 25mm wide. That's the stuff that the electrician seemed to have used on the other sockets. I just wondered about the cavity as I had built the wall back up and could gain access easily.

One question the original electrician didn't channel into the brick, so I'm guessing I need a thickish coat of plaster over the top.

How would you go about channelling into brick if that's a better idea?

 

[planemad]

There is a recent housing development where they built the internal thermal block walls, then ran plastic conduit on the outside for all the services [electric, phone, music system, cat5, central heating, etc] then insulated and the outer skin built.

Made it very neat and tidy and to a good standard so anything could be replaced when required, and a number of spare positions supplied too. All very impressive and all in the cavity.

Planemad is sitting here wondering what happens when the Sky man, Virginmedia man or aerial man comes and drills his 20mm hole through both skins and takes out your heating,electric and services

 

[ban-all-sheds]

To say nothing of boiler man or tumble drier man or cooker hood man with his 150mm core drill....

 

[LoveRocket]

One would hope that these men would not drill through safe zones. Or do you assume that SUNRAY's local builders have ran the services in a willy-nilly zig-zag fashion, just because they can?

 

[RF Lighting]

Do you really think that plumbers sre that clever?

I went to a job where a plumber was installing a boiler above a CU.

He started drilling the 4" hole for the flue around the same time all the power went off.

 

[LoveRocket]

Do you really think that plumbers sre that clever?

I went to a job where a plumber was installing a boiler above a CU.

He started drilling the 4" hole for the flue around the same time all the power went off.

 

[Monkeh]

Do you really think that plumbers sre that clever?

I went to a job where a plumber was installing a boiler above a CU.

He started drilling the 4" hole for the flue around the same time all the power went off.

Shame it went off, he deserved a good shock.

 

[ban-all-sheds]

Oh I don't know about that.

A bit of temporary flash blindness and a wrecked core drill, yes....