How deep for a trench for Swa?

[Lemmie]

Hi i need to dig a trench to lay cable for the garage electrics. The run is being used as a flower bed at the moment. Would 18" be okay?

I know i need to lay warning tape too, but would a layer of gravel be required before laying cable?

Thanks in advance.

 

[NuttallsSpark]

The regs say 2 Foot deep with a gravel base for drainage then as you stated warning tape. Plus try and keep it as straight as possible no diagonals

I know its a pain diggin that deep but if a jobs worth doin its worth doin right

 

[Lemmie]

Ah, more digging to do then.

thanks

 

[ban-all-sheds]

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http://www.tlc-direct.co.uk/Book/7.13.3.htm
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[Jaymack]

The regs say 2 Foot deep with a gravel base for drainage then as you stated warning tape. Plus try and keep it as straight as possible no diagonals

What Regs state this?
Gravel base is not recommended, sifted soil or sand is.
Why is drainage needed?, depends on topography whether this would be achievable, even if relevent.
Cable should be snaked in the trench to allow for subsidence.
Make an acurate drawing of the trench layout/route for records.
Jaymack

Trust me, my name is Shipman: - Doctor to you.

 

[Stoday]

You'll find some useful advice on the position of underground services here:
http://njug.co.uk/publications.htm
NJUG is the National Joint Utilities Group set up to standardise underground services. NJUG7 has the information you want.

 

[ban-all-sheds]

It's 29MB - hope you've got broadband.....

 

[Stoday]

It's 29MB - hope you've got broadband.....

Thanks for pointing that out, BAS.

I don't know why it's 29MB - the copy I downloaded a couple of years ago is only 607kB.

Anyway, it's as well you gave me the incentive to look at that site again because I see than NJUG7 has been superseded by "Utilities Guidelines on Positioning and Colour coding of Apparatus", which is 607KB. It includes the useful diagram showing locations and depths on page 9.