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"TNC" SYSTEM
To measure the currents deriving from faults, place the clamp over the PEN Earth connections.
Figure 11:
Configuration in TNC system.
"TNS" SYSTEM
To measure the currents deriving from faults, separate the PE wire from the active wires.
Figure 12:
Configuration in TNS system.
2.3.3 "IT" SYSTEM
To measure the fault currents, clamp the active conductors (Neutral included when distributed).
Please note that the intensity limit for the current resulting from the fault is obtained either by inserting
an impedance between a supply point (generally the Neutral supply) and Earth.
Figure 7:
Configuration in IT system.
Power supply earth
1, 2, 3 : measurement points
Power supply earth
1, 2, 3 : measurement points
Power supply earth
1, 2, 3, 4, 5 : measurement points
