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GMC-I Messtechnik GmbH 41
8.7.1 Protective Conductor Current – IPE
1
Adapter AT3-IIIE, AT3-IIS or AT3-II S32:
Voltage measuring inputs for leakage current measurement with differ-
ential method (instrument with feature I01)
2
Voltage measuring inputs for leakage current measurement with differ-
ential method and use of a current clamp sensor with (instrument with
feature I01)
Applications
Protective conductor current must be measured for protection
class I devices.
Definition of Protective Conductor Current (direct measurement)
Current which flows through the protective conductor in the case
of housings which are isolated from ground.
Definition of Differential Current
Sum of instantaneous current values which flow via the
L and N conductors at the device’s mains connection. Differential
current is practically identical to fault current in the event of an
error. Fault current: current which is caused by an insulation
defect, and which flows via the defective point.
Definition of Alternative Measuring Method (equivalent leakage
current)
Equivalent leakage current is current which flows through the
device’s active conductors, which are connected to each other
(L/N), to the protective conductor (SC1) or to the exposed, con-
ductive parts (SC2).
Differential Current Measuring Method
The device under test is operated with mains power. The sum of
the momentary values of all current which flows through all active
conductors (L/N) at the mains side of the device connection is
measured. The measurements must be performed with mains
plug polarity in both directions.
Alternative Measuring Method (equivalent leakage current)
A high-impedance power supply is connected between the short-
circuited mains terminals and all exposed metal parts of the hous-
ing (which are connected to each other). Current which flows over
the insulation at the device under test is measured.
Protective Conductor Current Measuring Method (direct measure-
ment)
The device under test is operated with mains power. Current
which flows through the PE conductor to earth at the mains side
of the device connection is measured.
Note
Regardless of the currently selected connection type, all
help images and schematic diagrams can be queried for
the selected measuring function.
Direct Measuring Method
–
Direct measurement type
– DUT mains plug to test socket
– APPs to APP sockets
Schematic Diagram
The device under test is operated with mains power.
Protective conductor current is measured between the protective
conductor at the mains and the protective conductor terminal at
the DUT via the DUT’s mains cable.
The special case involving “all APP sockets connected to PE
potential” can be selected.
Wiring Diagram
Differential Current Measurement
–
Differential measurement type
– DUT mains plug to test socket
Schematic Diagram
The device under test is operated with mains power.
Differential current is measured between mains conductors L and
N (current clip concept).
Single measurements, rotary switch level: green
Sw
it
ch
Po
si
ti
o
n
Measure-
ment Type
With Mains to
Test Socket Measure-
ment Type
Without
Mains to Test
Socket Measuring Functions
I
PE
Direct
I
PE
Protective conductor current,
RMS
I
PE ~
AC component
I
PE=
DC component
U
LN
Test voltage
Differential
I
PE
Protective conductor current,
RMS
U
LN
Test voltage
Alternative
I
PE
Protective conductor current,
RMS
U Test voltage
AT3 adapter
1
I
PE
Protective conductor current,
RMS
U
LN
Test voltage
Clamp
2
I
PE
Protective conductor current,
RMS
U
LN
Test voltage
I
PE