Mains cable depth

[Pete]

Has anybody any advice on the depth of mains elec cable? ENWL official diagram mentions a depth of 750mm but when the surveyor came out he said 450mm should be plenty. The cable will be inside 117mm red duct and sited in a private driveway. What I do not want is to bury it at the shallower depth and then they turn up to connect it and say you have not laid it at the correct depth. Plus not sure if this should be in a different thread but how have people laid all the cables together? A local groundworker said he dug a 600mm trench and laid all at same level and covered in sand but that seems very expensive use of sand and over kill on trench size. My initial thoughts where to use a 300mm trench and have water at the bottom and then elec but with ENWL wanting the elec cable deeper it throws a spanner in the works. I am only laying elec,water and comms duct. TIA

[recoveringbuilder]

Yes it seems to be 450mm and water is 750mm

[ProDave]

Water is 900mm in Scotland.

 

Separation between services 300mm which you can just get in a 300mm wide trench.

[recoveringbuilder]

No definitely 750 for water just checked our paperwork 

[Russell griffiths]

The way I view it is if you do a narrow trench and put one on top of the other, what if you need to work on the lower one

i would do a wider trench with separation between them.