I am reminded of this incident.

BBC Sport - Horse Racing - Newbury horse deaths caused by electrocution

Perhaps your local M.P. or the National Press should be told about your concerns..

I wonder just what type of cable is run in that ducting in your photos. More than likely steel wire armoured I would say.

Z.

From a BS 7671 point of view (this is a wiring regs forum) there is no specific depth specified - simply 'sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground'. Obviously digging trenches for other services and the like can't come under 'reasonably foreseeable disturbance of the ground' otherwise every service would have to be deeper than every other service, including itself, and the logic would break down; so we're really only thinking about ordinary day-to-day or routine maintenance sort of ground disturbances - digging in a garden or ploughing a field sort of thing, or periodic resurfacing . So how deep is deep enough depends very much on the circumstances. The NJUG likes different depths for different services partly to allow easy segregation of services, and to allow for routine resurfacing and minor changes in surface levels that often occur on roads/pavements (dropping of kerbs and so on). In other circumstance even 10mm of cover might be satisfactory. It all depends on the situation.

I've not read the legislation you refer to, but I guess it doesn't explicitly state a minimum depth for cables.

I'd not worry about the sand - that's only really needed where the soil contains sharp stones which could damage the cable (so it sometimes get specified regarldess if the ground conditions are unknown) - there's little need for it otherwise, or as appears to be the case here, the cable itself if protected by a twinwall duct.

In open field kind of sitations a lot depends on how its likely to be used - if it's the village common kind of place that often hosts fairs or circuses that routinely drive in tent pegs and the like, I'd like to see the cable reasonably deep. If however it's just used by dog walkers and the like, almost any depth is likely to be OK.

   - Andy.

Highly unlikely that a SWA, with an earthed armour, a plastic oversheath, and in a twinwall duct, would pose any risk to anything on the surface. Even if it did, it would have to be many metres deep (3m - 8 m perhaps) to avoid the risk.

   - Andy.

I am left wondering why this is troubling you.

Just what can be driven into a lawn or open grass land?

Z.

Thank you for all your replies.

I am not an electrical engineer but believe that where regulations apply, they should be adhered to.  My council is very adept at cutting corners, not adhering to legislation, mismanagement of the truth to name a few.  They have history of this on other projects.

Thanks again.

GG

Thanks, but I am trying to find out the correct info before I go down this line.

Cheers

Thanks for your reply.

Croquet hoops.

tent pegs perhaps...