Jordningsmätare

Jordningsmätare, also known as earth testers or ground resistance meters, are instruments used to measure the resistance of an electrical ground connection. This resistance is a critical factor in ensuring electrical safety and the proper functioning of electrical systems. A low ground resistance is essential to safely conduct fault currents away from equipment and personnel, preventing electric shock and damage.

These devices typically operate by injecting a small current into the earth electrode and measuring the resulting voltage drop. By applying Ohm's Law (Resistance = Voltage / Current), the instrument can calculate the earth resistance. Different types of jordningsmätare exist, employing various methods such as the two-point, three-point, or four-point (Kelvin) method. The three-point method is common for measuring the resistance of a single earth electrode, while the four-point method provides higher accuracy by eliminating the influence of the test leads and contact resistances.

Jordningsmätare are indispensable tools for electricians, maintenance technicians, and safety inspectors. They are used during the installation of new grounding systems and for periodic testing of existing ones to ensure compliance with safety standards and regulations. Regular testing helps identify potential issues such as corrosion, loose connections, or changes in soil resistivity that could compromise the effectiveness of the grounding system. The results obtained from a jordningsmätare are vital for verifying the integrity and reliability of electrical safety measures.