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TN-S-/TT system Pages

By the use of residual current monitoring systems, a message is given to the user before the shutdown threshold of an RCD is reached. RCMs (Residual Current Monitors) monitor residual currents in…

Continuous availability, operational reliability and cost efficiency through permanent residual current monitoring Pages

Comparison of the necessary insulation resistance measurements with an RCM-monitored electrical system The following section compares conventional DC insulation resistance measurement with the…

How does residual current monitoring work? Pages

All conductors of the outgoing circuit to be monitored (except the PE conductor) are routed through a measuring current transformer. In a fault-free system, the sum of all currents is equal to zero…

Why residual current monitoring? Pages

Comprehensive information Clear information centrally indicated on an LC display Transparency of all safety-related information through data transfer via bus systems and integration into…

Signalling instead of switching – Residual current monitoring in earthed systems Pages

In TN systems, the star point of the feeding transformers is connected to earth through a low impedance and the exposed conductive parts of the electrical installation are connected to the…

IT system: Unearthed systems for maximum availability Pages

As input to unearthed IT systems, either a transformer or an independent power source, such as a battery or a generator are used. Since no active conductor is connected to earth with a low…

IT systems as reflected in the standards Pages

Figure 13: The second fault in the IT system In accordance with IEC 60364-4-41:2017-03, subclause 411.6.4, after an initial fault occurs, the conditions for an automatic disconnection following a…

Insulation resistance - testing, measuring, monitoring Pages

During periodic tests the measurement of the insulation resistance is part of the measurements to be undertaken in accordance with DIN VDE 0105-100 (VDE 0105-100):2009-10. The insulation…

Control circuits as an IT system Pages

Conclusion A standard-compliant version of control circuits does not necessarily have to be earthed. Especially when considering the aspects of operational safety, failure prevention and cost…

Ungrounded system: Application examples Pages

Many loads are only switched on in an “emergency” (e.g. fire pumps, slides, all types of heating, etc.). Whilst they are offline, however, moisture or other factors can cause insulation faults in…