Schutzleiterverbindungen

Schutzleiter, or protective earth conductor, is a safety conductor used in electrical installations to connect exposed conductive parts of equipment and certain extraneous conductive parts to earth. Its primary purpose is to provide a low-impedance path for fault currents and to establish a defined earth potential, thereby reducing the risk of electric shock.

In normal operation the protective earth carries little or no current. In the event of insulation failure or a fault that energizes metal parts, fault current flows through the protective earth to earth, triggering protective devices such as fuses, circuit breakers, or residual current devices to disconnect the supply. The effectiveness of the Schutzleiter path depends on a continuous, low-impedance connection from the equipment to the earth.

Constructively, the protective earth conductor is typically green-yellow insulated copper (or equivalent) and is connected to all exposed conductive parts of equipment as well as to the building’s earth network. It is integrated into terminals, sockets, and housings to provide a secure PE connection. In many regions, protection contacts on sockets and plugs are designed to furnish the PE path.

In electrical distribution, the protective earth is part of earthing arrangements such as TN, TT, and IT systems and is often complemented by equipotential bonding between conductive parts to limit touch voltage during faults. It is not intended to carry normal operating currents except in fault conditions.

Standards require a reliable PE path and regular testing. Installations are designed so the PE path maintains continuity, and inspections verify that protective conductors are intact and properly connected. International and national standards for electrical installations, such as IEC 60364 and its European variants, address PE requirements and practices.