Thanks all for your great advise.
I've been asked to put a letter together to show how I have adhered to the regulations. Would you mind running your eyes over it before I post it to both client and driveway company. Any suggestions would be most appreciated (keep it clean!) Thanks.
See below:-
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Electrical installation at ********
Gates, lights and intercom
One of the restrictions we faced was disturbing the existing driveway as the new drive was going to be laid directly on top.
Burying the cable to a sufficient depth with no other protection is just one way of protecting it from damage, but not the only way.
The regulations clearly state “deep enough so as to not to get damaged” there is no specific requirement on depth for private land, only that it has to be adequately safe from any disturbance of the ground reasonably likely to occur during normal use of the premises.
The risk of mechanical damage due to external influence was assessed to be very low and so the following steps were being taken to reduce the possibility of damage to the cable:
- Cable was run around the periphery of the driveway, adjacent to a brick wall
- Cable was encased in concrete
- Earthed armoured cable was used
- Marker tape over concrete (driveway on top)
- Protected by an RCD (requirement 411 .3.2 Automatic disconnection in case of a fault)
- Plans drawn up showing cable routes
The following regulation was copied from the BS 7671 - 18th Edition - IET Wiring Regulations book and split into 3 parts as follows:
Regulation 522.8.10
- Except where installed in a conduit or duct which provides equivalent protection against mechanical damage, a cable buried in the ground shall incorporate an earthed armour or metal sheath or both, suitable for use as a protective conductor.
- The location of buried cables shall be marked by cable covers or a suitable marker tape. Buried conduits and ducts shall be suitably identified.
- Buried cables, conduits and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground.
I have consulted with the NICEIC and also received positive feedback from a recognised professional electrical forum.
Therefore, I wholeheartedly believe that I have adhered to all the regulation guidelines laid down by BS 7671 - 18th Edition - IET Wiring Regulations.
Please review this letter and respond back within 10 days
Yours Sincerely