Misc underground questions

[Alan Ambrose]

Coupla questions I couldn't find an answer for:

 

+ can I run a MDPE water pipe below a 110mm rainwater drainage pipe in the same trench? I plan to put a bunch of power / network stuff above that lot too (in their own ducts). For instance, Essex & Suffolk Water has the diagram below, but doesn't show drainage pipes.

 

+ when I cross an open ditch do I need to be way below the bottom of it (UKPN docs suggest 1m) as though it was level ground? Simiarly under a piped culvert?

 

[Alan Ambrose]

Also, where there's several power lines that run parallel for a bit - do they need 100mm separation too?

[Alan Ambrose]

Also ...

 

+ how do people generally seal the ends of ,say, an armoured cable in a 63mm duct?

[JohnMo]

I used stainless steel mesh and expanding foamed in to stop mice etc. then sealed with mastic to stop water etc.