Advice please depth of buried cable

[CourtneyDesigns]

Hi all
Can anyone tell me is there a legal requirement to bury exterior armoured cable at a particular depth or is it just a recommendation. I am not an electrician but am in dispute with a company.

Any advice would be appreciated.
Stuart

 

[Guest 004]

700mm should suffice

 

[malcolmsanford]

If you have a BS 7671-2008 regs book then regulation 522.8.10 is the guide to take. The last sentance is

" Buried cables, conduits, and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground"

A rule of thumb is in a garden below one and half spade length or below 500mm and under drives and such under between 500-750 mm.

 

[Electricalserv]

Last on e I did 2feet = 600mm for buried SWA

 

[Guest 004]

You need to take into account the soil thermal resistivity, and the ambient ground temperature

 

[CourtneyDesigns]

Just to explain a little further
We were installing a fence for our client on a barn conversion. We hit a swa cable ( for lighting bollard) that was buried approx 4 inches.They new where the fence was to be situated. They are now trying deduct £400 off the oustanding balance.
Thanks

 

[Electricalserv]

Just to explain a little further
We were installing a fence for our client on a barn conversion. We hit a swa cable ( for lighting bollard) that was buried approx 4 inches.They new where the fence was to be situated. They are now trying deduct £400 off the oustanding balance.
Thanks

The regs (which aren't law) just state a suitable depth. Now your version of a suitable depth and theirs may differ. You should have been made aware where the cable was and you should have had a banksman looking for it when digging. If the distributors buried the cable I.E scottish power.... they just lob them in I've seen some 2 inches deep (really).

It is going to be extremely hard for you to get yourself out of this one....

 

[Guest 004]

There is no law on the depth, only recommendations

 

[CourtneyDesigns]

But surely as they new where the fence was to be installed they should have taken this into consideration when burying the cable for the lighting bollard, or at the very least marked the cable with sand and or tape. (Buried cables, conduits, and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground)

 

[Engineer54]

The normally recognised depth for direct buried and ducted cables is 600mm, This is pretty much the cable manufacturers general recommended cable laying depths. Much more than that and you start encountering de-rating factors for the cable(s)...

Under paved or concreted driveways, where it is unlikely to be disturbed in the foreseeable future, this depth can be reduced to around 450mm. In gardens and the like, it is preferable, if not sensible to run cables in heavy duty conduit or pipe, Which also saves on a hell of a lot of sifting of the back-fill soil to get rid of sharp stones, that can penetrate the outer sheaths of cables.


So Courtney Jones, ...What is the arguement with this company on the burial depths of your cable(s)????

 

[Engineer54]

Haha, ....Just reread your further posts here!! 4'' depth won't conform to any recommendation, there isn't even room to lay a warning tape at that depth. Whatever contractor laid electrical cables at that ridiculous depth, should expect them to be damaged, even by there own work force, ...Total nonsense!!!

 

[Electricalserv]

But surely as they new where the fence was to be installed they should have taken this into consideration when burying the cable for the lighting bollard, or at the very least marked the cable with sand and or tape. (Buried cables, conduits, and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground)

How deep was the cable? When was it buried? At the end of the day there is no set in stone depth a cable must be buried.

If you did not know there was a cable there....

My argument would be (for you)..... Why was I not made aware where the cable was?.....if you knew a cable had been buried there, recently, why was I not provided with the information? and why was there no arrangements made for a banksman to be present. For those reasons the disturbance to the cable falls liable to your company for not informing us of its presence and also for not providing suitable bodies to help with the digging process.

What cable was it etc??? SWA?

Edit now see the 4 inch depth.....

 

[PC Electrics]

Can we take it that 'you' are fencers? You were given plans for where a fence should be erected, yes?

Did those plans (or any other information) give warning of any buried cables?

Was this cable newly installed or has it been there years (you haven't really told us much about the background to the work).

Assuming yes, yes, no and new:

i think you are being stitched up on 2 counts:
1. How could you possibly know there was a cable there? If it was running across open ground then 'guidance' would suggest it should have been deeper. Regulation 522.8.10 would also require warning tape. You infer there was none.
2. you are being charged £400 for a £150 (max) job. if this was SWA cable (3 core?) then a proprietory underground joint kit would be about £15. if it was an emergency job and the spark had to go to a wholesaler and back, then you could reasonably expect to be charged half a day.

 

[PC Electrics]

If the cable was recently installed and you were not warned of its presence, then presumably you hit a live cable? Lucky your digger wasn't electrocuted or suffer a shock. Those three dread words come to mind (for your benefit): Health and Safety. Throw that at them.

 

[CourtneyDesigns]

we were sent this computer generated picture and asked to replicate this fencing,which we did. It was not a large job so posts were dug by hand.We werenot informed of situation of cables but we could see the lighting bollards. I feel that as the knew the plans of where the fencing would be installed they should have buried the swa cable much deeper.