The Potential equalization refers to a highly electrically conductive connection between conductive bodies—such as the enclosures of electrical equipment—that prevents or at least significantly reduces the occurrence of different electrical potentials, and thus electrical voltage, between these bodies. At the same time, the equipotential bonding helps to Ground resistance of a system. The standard DIN VDE 0100 Part 200 precisely defines equipotential bonding as an electrical connection that brings the bodies of electrical equipment and external conductive parts to the same or approximately the same potential.
Why is equipotential bonding necessary?
In any electrical system, potential differences between conductive components can arise due to fault currents, different grounding points, or external influences such as lightning strikes. If, for example, a Ground Fault, a fault current flows through the grounding resistance. According to the Ohm's Law (U = R × I) This inevitably results in a residual voltage between the faulty component and ground—and thus potentially also relative to other accessible, conductive parts in the vicinity. This residual voltage must be limited to safe levels by using short connecting conductors with a sufficiently large cross-sectional area in order to effectively protect people from dangerous touch voltages. Equipotential bonding is therefore a key safety measure in electrical safety and is required in virtually every industrial and commercial facility.
Equipotential Bonding in Measurement Technology
Even beyond the realm of personal safety, the equalization of potential differences plays an important role in measurement technology—though here, primarily with regard to the Signal Quality. If multiple measuring devices, sensors, and a PC are connected to each other via their grounding points, even small potential differences between these points can lead to unwanted equalization currents flowing through sensor or communication lines. Such so-called Ground loops These signals are superimposed on the actual useful signal in the measurement path and can significantly distort sensitive measurement values—especially at low signal levels, over long cable runs, or in environments with electromagnetic interference.
Practical Application in Delphin
The measuring and testing equipment from Delphin Technology address this issue through a consistent electrically isolated Interpretation of the analog signal inputs. The potential isolation at the signal inputs and outputs electrically decouples the individual measurement circuits from one another, so that ground loops and potential shifts cannot lead to equalizing currents in the measurement circuit in the first place—regardless of whether the system also features a conventional equipotential bonding system in accordance with VDE specifications. This galvanic isolation, in combination with sensors connected without grounding, ensures that Delphin measuring instruments reliably deliver accurate and safe measurement results even over long cable runs, in industrial environments with EMC interference, or when measuring live components.