running swa in building footings

[GT1]

Current project is a single story extension for a client involving DNO moving supply, relocating and new CU, first fix, second fix.

Client also wants to run some SWA to the garage. The most logical route, as they are already dug, is to lay the cable in the (very deep) footings of the extension once the first few courses of block are in place.

If the builder agrees, I'll bring the SWA out at the exisiting corner of the house, after a short run through the cavity, into the new cavity for a few inches then exit into the footings to run alongside the blockwork at depth.

I'll obviously use some soft sand top and bottom of SWA and warning tape etc.. my only niggle is running the cable in the footings alongside the blockwork. I'm pretty happy theres nothing in 17th stopping me, however does anyone know of any building code or similar that would be an issue..? (for the record the SWA would be about 5' undergound running parallel to brick alongside new extension until crossing a smal path to garage).

 

[Richard Burns]

Lots of luck doing any repairs on that cable at a later date!
If you really want to bury it 5' deep then I would at the very least put it in ducting so it could be replaced later and also it would provide protection from the the builders wrecking it whilst making the walls.
Far better to have it 600mm deep if it is laid direct and after the builders have finished the footings.

 

[GT1]

It can go at any depth to be honest the footings are just that deep now. I'll be waiting til the brickies are clear and will put cable in as the footings are filled in.

 

[Richard Burns]

That sounds a lot better.

 

[GT1]

Yeah that was always the plan, to incorporate the swa as the trench was filled in. I was just concerned in case there was any building regs about services sharing a trench with with footings. Can't think why there would be mind you..!

 

[James-]

Just place it in a larger pipe like perforated land drain for future repair work

 

[James-]

Just place it in a larger pipe like perforated land drain for future repair work

 

[Engineer54]

The footings trench is going to be filled with concrete to almost FGL before they start building the extension walls!! 5' deep footings seems to be a bit of an overkill to me normally they would be a metre deep X 60+cm, especially if this extension is a typical single storey affair.

As suggested run this SWA cable in a PVC duct, not that you'll have much chance or hope of ever being able to repair or replace said cable in the future, going by your description of the routing....

 

[GT1]

Yes indeed it's only a short run to the garage. If it ever needed to be looked at in the future it would be easier to just replace for new down a different route.
The footings are so deep at the mo due to having to deal with a sewer pipe.

 

[Rockingit]

The footings trench is going to be filled with concrete to almost FGL before they start building the extension walls!! 5' deep footings seems to be a bit of an overkill to me normally they would be a metre deep X 60+cm, especially if this extension is a typical single storey affair.

As suggested run this SWA cable in a PVC duct, not that you'll have much chance or hope of ever being able to repair or replace said cable in the future, going by your description of the routing....

There's some bits of my footings (just building our own 2 story extension) that are over 2m! Just depends on what the ground is like and what you've got too work around (in my case, previously disturbed ground so need 150 below that lowest point).

 

[GT1]

Yes this one looks like something out the First World War !!

 

[Engineer54]

There's some bits of my footings (just building our own 2 story extension) that are over 2m! Just depends on what the ground is like and what you've got too work around (in my case, previously disturbed ground so need 150 below that lowest point).

Jesus, 2m footings for an extension to a domestic house, never seen that before. Seen 2m slaps for a 4 story building though!! lol!!

Remember when my parents had a single storey extension build, the footing were 1m X 0.8m The bloody house footing were only a couple of feet deep.... The extension footings went under the original footings where it met the house. In Victorian times and before, they didn't even bother with footings, build straight on to virgin ground!! Look how long they have lasted!! lol!!