Maadoitusjännitteiden

Maadoitusjännitteet, also known as ground voltages or touch voltages, refer to the electrical potential difference that can arise between a grounded surface and a person or animal in contact with it. These voltages are a critical concern in electrical safety, particularly in situations where faults or abnormal conditions occur.

When an electrical fault happens, such as a live wire coming into contact with a metal enclosure that is connected to the earth, a significant current can flow into the ground. This current flow causes the earth itself to become conductive, and the resistance of the soil leads to a voltage drop. Consequently, different points on the ground surface may have different electrical potentials.

A person standing on the ground and touching a grounded object that is at a different potential than the ground beneath their feet will experience a touch voltage. Similarly, if a person is standing on the ground and another person or animal touches them, a step voltage may occur, which is the potential difference between two points on the ground separated by a certain distance (e.g., the distance between a person's feet).

The magnitude of maadoitusjännitteet depends on several factors, including the magnitude of the fault current, the resistivity of the soil, the grounding system's design, and the configuration of the grounding electrodes. High ground voltages can be dangerous, potentially causing electric shock. Electrical safety standards and regulations aim to limit these voltages to safe levels through proper grounding design, fault current limitation, and the use of protective devices like residual current devices (RCDs). Monitoring and measuring ground voltages are important aspects of ensuring electrical system safety in various environments.