marklight999

 Dear Crossy, thank you so much for the information. I will have three hot water heaters for three bathrooms, washing machine outside, some cooking appliances in kitchen, refrigerator,  and electric water pump also outside. I have some questions below:
1 - should i install RCBO breakers for each hot water heater since there is electrical wires routed for each to the main breaker box. I just want to make sure to protect from electric shock but lacking knowledge. 
2 would it be beneficial to install a separate copper rod for two hot water heaters, washing machine and the house water pump?
3 The diagram show one earth ground copper rod be installed at the  main breaker, will it be sufficient or would it be beneficial to install multiple earth ground copper rods at different locations? Ideally how many will i need for the house (200 sq m), single floor?
4 Other than to have RCBO breakers,  do i need the same for washing machine and electric water motor or can I  install GFI outlet is sufficient?
Many thanks for your input. 

If i need to earthed or ground the water heater in bathroom, do i need to install the 2.4 meters copper rod in the ground or there is alternate method? I am not trying to look for shortcut, but to make sure it will be done properly since have children in the house. 

I have just build a house in Phetchabun. The wiring is in place for hot water heater in each of the three bathrooms. Each bathroom set up for hot water heater have three wires, white, blue and green/yellow. I have also bought Renai shower water heater but not installed yet.

I think there is dedicated breaker in the main breaker for each water heater in place. I am checking to see if the house main breaker box is earthed.

If the main breaker box is earthed and the water heaters are connected to main breaker box, do i need to earth each water heater for each bathroom separately or wiring the the main breaker box is sufficient? 

What is the blue and green/yellow wires for?

Thank you.