Main incomming supply to domestic residence

[donkidonki]

A friend of mine recently discovered that a neighbours main electrical supply runs through her garden, less than a foot below the surface and in non-armoured cable. She found this out when her spade exploded. (luckily without injury)

The electricity supplier tried to charge her for the repair costs to the cable, which they dropped when she then insisted that she did not want her neighbours supply in her garden; she has not heard from them since.

During the less than helpful conversation with the supplier, my friend questioned the legality of such a supply being run in a non-armoured cable, in un-marked shallow ground. (The cable was struck though soft earth, no gravel or similar was laid on top of the cable.) The supplier stated that there is no legal regulation for the supply cable, and they can leave it wherever they like!


My question is, is that cable legal? Surely it should be buried much deeper, armored cable, and gravel or similar should be covering it as to give a warning when digging? Not to mention, whether it can be laid in such a way when it is not even a supply to your property? (ok, make that, questions)

Considering the amount of regulations concerning the distribution of electricity within a building, it seems ridiculous that the main incoming supply could be so lacking in regulation

 

[FingRinal]

She could try Ofgem, but they'll probably direct her to the thing that has just replaced Energywatch - which will probably be of no use for the type of complaint she has. The Heath and Safety Executive might be a better bet. There's nothing like a bit of danger to set these heat seeking ferrets into action. After all her gardener would be at his place of work when he next comes into contact with the cable.


From Electricity Safety Quality Continuity Regulations 2002:-

PART IV- UNDERGROUND CABLES AND EQUIPMENT

General restriction on the use of underground cables
12. No generator or distributor shall use any of his underground cables and associated equipment (except those in generating stations or substations) which he knows do not comply with regulations 13 and 14.


Excavations and depth of underground cables
14. - (1) Every underground cable shall be kept at such depth or be otherwise protected so as to avoid, so far as is reasonably practicable, any damage or danger by reason of such uses of the land which can be reasonably expected.

 

[holmslaw]

..

 

[Steve]

The DNO dont use non-armoured cable do they? Thought it was all concentric or armoured . . . Penetrating it will always cut off the supply.

Can the OP describe the cable? Concentric has one core (live) surrounded by the combined neutral and earth.

The only place I know that the DNO use non-armoured cables on the LV systems is on the sides of houses. These are brown and look like T+E, but without the E.

 

[Lectrician]

If it was not an old lead sheathed type cable it would with little doubt be a concentric or split concentric cable (could even be a waveformed concentric if three phase).

These cables have the neutral/earth surrounding the live(s) which means any object casuing damage will always short a phase to the outer neutral and earth and cause operation of a protective device, or simply blow the fault clear if you are un lucky.

The chances of a shock are negligable but should not be ignored. The chances of recieving burns are far higher.

Incidentally, a concentric cable will also ensure the neutral is the last conductor to break, giving greater safety to downstream supplies in the event of cable damage.

Armoured cables are not used as the steel wire armour rots over time, as us sparks know only too well. Obviously cost plays a part too.

The cables should be 450mm below the surface for LV, however, older installations are often less. There is also a chance the cable was not installed by the DNO but by builders or site workers during building and groundswork - this is quite common, and they simply sign to say the cable is the correct depth.

Guidelines for buried cables are tighter now that they have been, but you still see all sorts.