All installations have an earth leakage current that is mainly due to the conductor’s capacitive leakage and to anti-parasitic or EMI filtering capacitors, for example class I equipment. The sum of these leakage currents may cause highly sensitive residual protection – RCDs to trip. Tripping becomes possible from I∆n/2 without it endangering safety to personnel.
All installations have an earth leakage current that is mainly due to the conductor’s capacitive leakage and to anti-parasitic or EMI filtering capacitors, for example class I equipment. The sum of these leakage currents may cause highly sensitive residual protection – RCDs to trip. Tripping becomes possible from I∆n/2 without it endangering safety to personnel.
At the origin of a TT installation (and only in this case), it is possible to replace the detection toroid placed around live conductors by a single toroid linking the HV/LV transformer neutral to the earth.
– To avoid spurious tripping of RCDs protecting against indirect contact, for average sensitivity RCDs the device’s rated residual differential current (I∆n) must be higher than double the value of the leakage current (If) that flows during a first fault
Equipment is increasingly fitted with rectifying devices (diodes, thyristors, etc.). Earth fault currents downstream of these devices have a Standard EN 50178 stipulates the following organisation diagram which defines requirements when using electronic equipment behind a differential device.
Any electronic equipment which risks generating DC component fault current that risks interfering with the operation of the differential protective devices must be accompanied by a warning label which says so.
All installations have an earth leakage current that is mainly due to the conductor’s capacitive leakage and to anti-parasitic or EMI filtering capacitors, for example class I equipment. The sum of these leakage currents may cause highly sensitive residual protection – RCDs to trip. Tripping becomes possible from I∆n/2 without it endangering safety to personnel.
All installations have an earth leakage current that is mainly due to the conductor’s capacitive leakage and to anti-parasitic or EMI filtering capacitors, for example class I equipment. The sum of these leakage currents may cause highly sensitive residual protection – RCDs to trip. Tripping becomes possible from I∆n/2 without it endangering safety to personnel.
At the origin of a TT installation (and only in this case), it is possible to replace the detection toroid placed around live conductors by a single toroid linking the HV/LV transformer neutral to the earth.
– To avoid spurious tripping of RCDs protecting against indirect contact, for average sensitivity RCDs the device’s rated residual differential current (I∆n) must be higher than double the value of the leakage current (If) that flows during a first fault
Equipment is increasingly fitted with rectifying devices (diodes, thyristors, etc.). Earth fault currents downstream of these devices have a Standard EN 50178 stipulates the following organisation diagram which defines requirements when using electronic equipment behind a differential device.
Any electronic equipment which risks generating DC component fault current that risks interfering with the operation of the differential protective devices must be accompanied by a warning label which says so.
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