Ground leakage current

Figure 21.1 as in lEC 60479-1 illustrates the various zones of ground leakage current versus duration of fault and its effect on a human body. 

The leakage current at hazardous locations such as refineries, petrochemical plants and mines should not exceed 15% of the rated current of the circuit or 5 A, whichever is greater. Table 21.3 indicates the maximum permissible ground leakage currents for such areas at 15% of the rated current and the recommended maximum ground loop impedances. 

The use of core-balanced CTs is quite common for such applications. They are specially designed to detect the ground leakage current of a circuit. This ground leakage is then used to trip the faulty circuit through a ground... 

Current rating of circuit Amp Maximum permissible ground leakage current C Amp Recommended maximum ground loop impedance on a 240 V phase to ground circuit 240... 

In fact, the parasitic capacitance is not connected symmetrically to the two input (rectified) dc rails. So why should the ground leakage current end up being shared equally by the two lines ... 

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