The latter represents a direct connection of the electrically conductive installations, systems and devices to the earth potential and protects persons against impermissible touch voltages which occur at operationally non-voltage-carrying conductive device parts and which could cause damage to health if touched.
Conductors in the low-voltage network: neutral conductor (blue), protective earth conductor (green-yellow) and current conductor (black).
The protective earth is connected directly in the mains plug and is led via this into the electrical equipment, where it is connected to the metallic parts such as the chassis. The three conductors can be identified by their colored insulation. The current-carrying outer conductor is black or brown, the neutral conductor is blue and the protective conductor is green- yellow.