I'm running a cable from my house to a site in my back garden where I am building a shed. The length of the cable run is about 7-8 metres. I have steel armoured cable which is OK for direct burial.
Is there any regulation for the UK about what depth the cable needs to be buried to? I've started digging a 'slot' but it is really hard going due to the number of stones under the turf.
This is the cable I am using:
https://www.amazon.co.uk/gp/product/B07B7DJZL8
as I understand it BS7671 requires that the cable is buried deep enough to prevent the cable being disturbed by any reasonably foreseeable disturbance of the land but does not specify a particular depth. There should also be a warning tape burried above the cable.
Normally though the recommendation for a domestic garden is around half a meter. That is enough to give it some margin beyond the depth of a typical spade.
If you will be be getting an electrican to connect up and certify this I would strongly advise talking to them first before you buy and install the cable.
You probably need to show the electrician the cable in the trench with the warning strip above it before you backfill it so he can satisfy himself about the depth. Without seeing it he may not be willing to sign the installation off and give you a certificate.
Regulations for GB is that buried armoured cable is at a depth of at least 18". If its not armoured,it could be pyrotenex cable or in suitable conduit.
Regulations are that cable is buried at least 18 inches. It must be SWA cable,or pyrotenex, any other cable must be in conduit and sealed against moisture. In a concrete floor,the SWA cable or conduit must be protected with an inch of concrete. Hope this helps.
I needed to install an exterior RCD-integrated twin wall socket for a forthcoming patio veranda, to power patio heater and LED lights each separately via 13A plug.
To the left of patio doors is a junction box feeding our workshop on a dedicated radial feed, directly sourcing from RCD-protected 32A MCB in the CU. To the right of the doors is the wall socket mounted ~0.7m from ground. I am tapping from the workshop radial in the junction box to power the twin 13A wall socket using 4mm 3-core SWA.
A 3-inch wide stone-filled patio drain channel runs between the wall and patio slabs, though is only ~200mm deep, so I laid 20mm solid conduit in the bottom of the narrow drain channel, with 20mm corrugated trunking joined to the solid with rigid plastic over-sleeve to allow for SWA bend radius up and a few inches where it emerges above the stones. Then, 2 x cable cleats at ~30mm pitch guide the SWA vertically to the SWA gland on the underside of the socket box.
I should also add that the black SWA wire is covered with green/yellow sleeve at each end. The brown wire naturally identifies Live, leaving grey for Neutral. The adjacent patio slabs are cemented down and significantly above the cable conduit.
The SWA outer is therefore protected against abrasion throughout, and the narrow stone-filled channel is not an area ever likely to see heavy digging tools.
Whilst not buried at the 'usual' prescribed depth, I'm trusting that common sense will prevail when it comes to inspection/notification.
