Running SWA Cable Under Concrete Footing

[GVC]

There is a two storey extension being built on the side of my house.

The footings have been dug out (1000mm ) and before being back filled with concrete , I want to run a 16mm SWA to an out building.

Can the cable be laid in the trench directly and the concrete poured over the cable? 

 

[Lurch]

No.

 

[Andy™]

what he said^

 

[GVC]

There is a two storey extension being built on the side of my house.

The footings have been dug out (1000mm ) and before being back filled with concrete , I want to run a 16mm SWA to an out building.

Can the cable be laid in the trench directly and the concrete poured over the cable or if the cable was placed in conduit or ducting

 

[Blue Duck]

something like this:

But I would put warning tape on top and run the cable in ELECTRICAL ducting.

Finding a fault in a cable that is buried in concrete is rather annoying and would require something like this

 

[Andy™]

Finding a fault in a cable that is buried in concrete is rather annoying and would require something like this

or this

http://static.plantminer.com.au/imager/index/540-338-0/hbBYrVo4thI4QHBUMriUaTm50Gc6C2nRIiUbD2f2F95L-5mmiGduZhbGUwi2_XruPynZUsjQ9ExkxGHb5gHMHA

 

[Blue Duck]

Is that an 800?

Why not make sure the job is done properly....

:lol:

 

[ProDave]

You say the footings have been dug 1 metre deep? well a cable does not need to go that deep.

So get the concrete poured, Then when the brickies start building up the walls, get them to build in a length of black ducting through the wall at the correct depth to feed your cable through.  If your builders are as particular as mine were, they will bridge even a small opening for a cable duct with a proper lintel.

 

[GVC]

Great idea

but the footings are coming up almost ground level

 

[ProDave]

You mean trench fill?

Bury a black duct in the trench fill.

 

[Murdoch]

Why not ask the sparky doing the electrics for his input.....

 

[Evans Electric]

The builder should be able to sort this for you ,   just lay a duct , accessible at the house end with a draw wire in it .

 

[kerching]

Builder has just put a duct in for me

black leccy duct 38/40mm, draw rope, perfect...well apart from the 90 degree solvent bends he fitted at each end to turn pipe upwards 600mm. Not the easiest to negotiate with a 10mm x 4 core :innocent

 

[Badger]

Shouldn't they be a hockey stick not 90degree bend 

 

[apprentice87]

You mean trench fill?

Bury a black duct in the trench fill.

I think he means "deep strip" footings.. I take it that it is clay soil??? They would be about a meter deep [min] and hen filled with concrete to nearly ground level..

View attachment 7968

 

[ProDave]

I have always known "deep strip" as "Trench Fill" it must be a regional thing, basically you are filling the whole trench with concrete (expensive)

I prefer the flexible black twinwall duct on a roll, easy to get nice gentle bends.

P.S Some DNO's insist you use red duct.

 

[apprentice87]

I like the twin wall stuff too!! Never knew some DNO's want red though..

john..

 

[kerching]

Around here Private duct is black

DNO is Red

 

[misssweden]

Around here Private duct is black

DNO is Red

What is this witchcraft?! 

 

[kerching]

What is this witchcraft?! 

Let it be so!

DNO only have 3 sizes

single phase 40mm

three phase 100 or 150

even though their smallest three phase will easily fit down the 40mm they will not allow its use even on a straight 2m run through foundations with no bends!

so I just it sub it out now, saves the hassle

handy as daughters best mates hubby owns a large Utilities/Civils company