Laying underground cable for electricity in the garden

Hello dear electricians,

I want to lay 2 underground cables with RCD switches / fuses into the garden, one for sockets (3x2.5 square) and one for lighting (3x1.5 square). The garden starts after about 15m of cable laying, so the cable length is already correct, I have checked that.

The question now is how I should lay the cable:

a) Can both cables be laid next to each other according to DIN standard (2 trenches deep, sand, tape, etc.) or do 2 power cables cause interference signals?

b) For the cable for the lighting, there should be 3 lamps connected, but the cable only has one end, how do I connect the lamps which are each 3m apart? Do I need to use something like an outdoor junction box at the cable end?

c) Do I have to earth the cables more fundamentally or otherwise?

d) How can I make it so that I can activate the outdoor lighting from the living room without having to go to the fuse box and switch the fuse on and off?

Thank you in advance for your effort.

C means: do I have to connect the cables to a foundation earth electrode in the utility room or is there another solution.

Hello, are you sure you want to do something like this yourself? To me, it sounds like saving money in the wrong place and possibly putting other people's lives and your own at risk. Nevertheless, here is my brief opinion without guarantee: For A: Shouldn't be a problem as long as you don't lay a data cable next to high voltage. For B: Junction box sounds good. For C: Oh man, get an electrician, normally there's a potential equalization rail in the sub-distribution of your house. For D: I can't help you with this now, there are also options via radio. And again, have it done by a professional electrician.

Is there a junction box for underground use? A waterproof one? How does it work?

The meter box is connected to a foundation earth electrode, is that sufficient? As mentioned, the cable goes into the box there.

Does anyone have an answer for me? Thank you all