Steve wrote:

I am about to fit a gate automation system and need to run a supply
cable ie: 3 core armoured with an additional 5 core intercom cable.
What depth do i need to lay the cable at and what additional
precautions are require to comply with building regulations

There are no absolute requirements for cable depth, you should use what
is sensible for the situation.

450mm is the normal suggested minimum depth, however you may need to
increase this is areas that are likely to be deeply "dug over" (flower
beds etc).

After you bury the cable you should backfill the first 150mm or so and
then bury a "cable below" warning tape (usually yellow plastic stuff -
you get it on long reels from electrical wholesalers etc) before filling
the trench. That way anyone in danger of digging to far will get to the
tape first.

It might also be wise to ensure that there are at least a couple of
inches of separation between power and signal cables along the full
length of the run (to eliminate mains hum on the signal circuits).

--
Cheers,

John.

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