Aarding

Aarding, also known as grounding, is the practice of connecting exposed conductive parts and electrical circuits to the earth. The primary purpose is to keep voltages at safe levels during normal operation and to provide a low-impedance path for fault currents so protective devices can disconnect the supply quickly.

A grounding electrode is installed in the soil and connected by a grounding conductor to the electrical installation. Common electrodes include ground rods, plates, or a buried mesh. The earth serves as a reference potential and a reservoir to absorb fault current. In most installations a protective earth conductor bonds exposed conductive parts to the earth, while a functional earth may be used for noise suppression or interference control on non-safety circuits.

Earthing systems are categorized to describe how conductors and the neutral are connected. The main types are TT, TN-S, TN-C, TN-C-S, and IT. In TT systems the installation has its own local earth electrode; in TN systems the building is connected to a shared earth network; IT systems use an isolated or high-impedance supply with earth connections for continued operation in case of a fault. The arrangement influences fault current paths and earth impedance, which in turn affects protection performance.

Regular testing is important to verify earth resistance and the integrity of bonding connections. Maintenance should follow applicable standards and procedures. Standards commonly referenced include IEC 60364 and national norms such as NEN 1010, which specify requirements for earthing design, installation, and testing.