Connecting earth wire with motor water pump
Q1: I would look at American bonding rules, in terms of what is legal as a ground rod. 

Q2: I recommend pigtailing your grounds.  That is, one wire comes from the panel, a second wire travels to the next outlet, and a third short wire goes to this outlet.   All three wires are spliced together using whatever method is legal.   The reason to "pigtail" is that you need to be able to remove an outlet for repair, without breaking the grounds to downstream outlets. 

Here are the best practices in the US, which are about as good as anywhere in the world. We create a well-established ground/earth connection with ground rods or bonding to a water pipe.  This ground wire goes to the main electrical panel (which contains the circuit breakers or fuses).  

As it happens, in the US we bond neutral to ground. That is debatable, best to follow local codes.  If this is done, do it in the main panel only! Do not bond at sub-panels or other locations, and never misuse ground as a neutral.

From the panel, we use metal conduit, or run a ground wire to every outlet, junction box, switch etc. in our system.  If the ground is being added later, it may be run separate from the other wires via any workable route, as long as the wire is not in danger of physical damage.  

For 30A or smaller circuits, US practice uses ground wire the same size as the main wire (bigger is allowed).  For larger cables, or in Europe, the practice is to allow a somewhat smaller ground wire.