Erdungsmessgerät

An Erdungsmessgerät, also known as an earth tester or ground resistance tester, is an electrical instrument used to measure the resistance of an earth electrode or grounding system. This measurement is crucial for ensuring the safety and effectiveness of electrical installations. A low earth resistance is necessary to provide a safe path for fault currents to dissipate into the ground, preventing dangerous voltage build-ups on equipment housings and reducing the risk of electric shock.

These devices typically operate by injecting a known current into the earth electrode and measuring the resulting voltage drop. By applying Ohm's law (R = V/I), the resistance can be calculated. Various methods exist for performing these measurements, with the most common being the two-point, three-point, and four-point methods. The choice of method depends on the accessibility of the earth electrode and the required accuracy.

Modern Erdungsmessgeräte are often digital, providing a clear display of the resistance value. They may also include features such as automatic ranging, battery level indicators, and data logging capabilities. Regular testing of earth electrodes with an Erdungsmessgerät is a standard practice in electrical maintenance and safety protocols, especially in industrial, commercial, and residential settings, as well as in power generation and transmission systems. Compliance with relevant electrical safety standards often mandates the use of such instruments.