Potentialausgleich

Potentialausgleich, or equipotential bonding, is the process of connecting exposed conductive parts of an electrical installation and, where appropriate, other conductive parts to the same electrical potential. The aim is to prevent hazardous differences in voltage that can occur during fault conditions, due to stray currents, or contact with different circuits. By maintaining equal potential, the risk of electric shock, sparking, or arcing between metal parts is reduced and the reliability of protective devices is enhanced.

There are several forms. Protective bonding (Schutzpotentialausgleich) ties together exposed conductive parts such as metal enclosures, water or gas pipes, and structural steel with the protective earth. Supplementary or extraneous bonding connects extraneous conductive parts that could become live, for example metal water pipes, gas pipes, and other building services, to the equipotential network. Functional bonding may be used to ensure proper operation of equipment by maintaining similar potential where safety is not the primary concern.

Implementation typically involves installing bonding conductors of appropriate size and routing them to a central bonding point or equipotential bonding bar, connected to the protective earth system. The exact requirements depend on local electrical codes and standards, such as the EN 60364 family (IEC) and, in many countries, national standards like DIN VDE 0100 series.

See also: grounding and bonding, earthing, protective earth, extraneous-conductive part.