The system earthing is a fundamental safety feature that protects people from electrical leakage by directing any fault currents toward the ground instead of through the human body.
A standard system requires the earth wire (yellow-green) to be connected to every socket, light point, and appliance. This network must then discharge the current through specific ground electrodes (earth rods) driven into the soil.
Warning: You must never use water or gas pipes as conductors for earthing. While this was a common practice in the past, it is now prohibited and extremely dangerous: in the event of a fault, the faucets and the water itself could become energized, leading to fatal electric shocks.
Equipotential Bonding
Although pipes must not serve as a discharge path, metal piping must be connected to each other and to the building's earth system via equipotential bonding. This ensures there are no voltage differences between the plumbing and electrical systems.
Remember: the combination of electricity and water is high-risk. Periodically checking the efficiency of the RCD (Residual Current Device or "safety switch") and the continuity of the earthing system is essential for your home's safety.