SWA cable

[Neil]

HI guys, Could you tell me what is the minimum depth for SWA cable in a garden. Also where to in the regs can I find it.

Thanks in Advance dudes/dudettes

 

[Des 56]

You probably wont find it in the regs
If you can install deeper than 500mm then someone with a spade will have little chance of spiking it
Its an estimation of when damage may or coukd occur rather than a particular depth

 

[Neil]

Own reply just found something in the wiring regs page 269 note 1... says 700 mm based on other values given. So dig 700mm, add 150mm sifted sand, lay cable (snake it), add 150mm sifted sand. tamp it, lay caution tape and back fill. job done!

grab a beer and enjoy.

 

[Des 56]

Thats a calculation for rating factors for a given depth and multiple cables
Its not a note on how deep a cable should be buried

Think two spades rather than a given depth
Warning notices yes,but you are not burying for archeologists to excavate in the distant future
Its for reducing the chances of damage
A maximum of 500 is more than enough for the most testing of environments

 

[Neil]

Ok! below 500mm is good. cheers

 

[Callum.]

Ok! below 500mm is good. cheers

Just for confirmation i learnt this is college like a week ago and they said it was 500mm too

 

[mogga]

just bear in mind thats 500mm to the top of the cable so a nice 600mm trench with a sand base ccable layed in then sand over the top to around tamp sand down 500mm then cover but remember not to infill with bricks/ect infill with small materials

 

[johnboy6083]

an alternative is to diga trench, lay ducting, andthe pull your cables thorugh that. This also makes it rewireable, without haveing to dig out your cable. It also provides some mechanical protection to the cable.

PS, if using this method, always pull a drawcord (blue rope) alongside the cable, as you can then add cables later on if needed

 

[mogga]

John Boys method is preferable but 500mm "Cover" would still be preferencial

 

[johnboy6083]

i agree mogga!

 

[GT1]

When i did my 17th last year.. the only thing mentioned on cable depths when buried, was that it needs to be "as deep as necessary"...

And to be fair havent found anything yet (in the regs) to contradict that..!

Obviously there is various "best practice" options available..

 

[Voltimax]

You also have to consider what will be going over top of it such as traffic i.e. will there be motor vehicle passing over it when it's buried? That's why no measurement is given, because you as the designer and installer have to use your judgment.

 

[johnboy6083]

so if its in a childrens playgorund, then not that deep, as children dont weigh much, but if outside a liposuction clinic, then it must be encased in concrete!

 

[mogga]

PMSL john

 

[Voltimax]

so if its in a childrens playgorund, then not that deep, as children dont weigh much, but if outside a liposuction clinic, then it must be encased in concrete!

Exactamundo