lisämaadoituksen

Lisämaadoitus, often translated as supplementary bonding or equipotential bonding, is a crucial safety measure in electrical installations. Its primary purpose is to ensure that all exposed conductive parts and extraneous conductive parts are at the same electrical potential, thereby preventing dangerous voltage differences that could arise during fault conditions. This is achieved by connecting these conductive parts to the main earthing system through additional conductors.

In a typical electrical installation, the main earthing terminal connects the protective earth conductor of the incoming supply, metallic water pipes, gas pipes, and other significant conductive structures. Lisämaadoitus extends this principle by connecting, for instance, metal casings of appliances, metal conduits, and other conductive elements that are not part of the normal current-carrying path. If a fault occurs, such as a live conductor touching a metal enclosure, the lisämaadoitus provides a low-impedance path for the fault current to flow to earth. This large current then causes the protective device, like a fuse or circuit breaker, to operate quickly, disconnecting the power supply and making the installation safe.

The effectiveness of lisämaadoitus relies on the continuity and low resistance of the bonding conductors and their connections. Regular inspection and testing of these connections are essential to ensure they remain effective throughout the lifespan of the electrical installation. In many countries, national electrical codes mandate the use of lisämaadoitus in various types of installations, especially in locations where the risk of electric shock is higher, such as bathrooms and kitchens. It is a vital component in preventing electric shock and ensuring electrical safety.