Operation Manual

GMC-I Messtechnik GmbH 19
9 Measuring Protective Conductor Resistance
Definition
Protective conductor resistance
is the sum of the following
resistances:
• Connector cable or device
connector cable resistance
• Contact resistance at plug
and terminal connections
• Extension cable resistance if
utilized
Resistance is measured:
• Between each conductive
part of the housing and the earthing contacts at the mains and the de-
vice plug (if a removable mains connector cable is used), or the protec-
tive conductor terminal for permanently installed devices.
• as 4-pole measurement
• Between the earthing contacts at the mains plug and the earthing
contacts at the device plug for device connector cables
• Between the earthing contacts at the mains plug and the earthing
contacts at the coupling socket for extension cables
Connecting Safety Class I Devices to the Test Socket
When the DUT is connected, resistance is measured between the protec-
tive conductor terminal at the test socket or at the PE jack and the probe
connection at the DUT (contact with conductive parts of the housing).
õ In order to measure protective conductor resistance, contact a
conductive part of the housing with the probe, which is connected to
the protective conductor.
During measurement, the connector cable must only be moved in as far as
it is accessible during repair, modification or testing.
If a change in resistance occurs during the manual test step of the conti-
nuity test, it must be assumed that the protective conductor is damaged,
or that one of the connector contacts is no longer in flawless condition.
Testing Extension Cables
See test sequence in chapter 15.7 on page 46.
Note
+
“Connection of the DUT: SC I/II” is not displayed when the test is
performed individually, but rather only during the automatic test
sequence.
Selecting Test Current and Polarity
Test current amperage (200 mA DC or 10 A AC (Feature G00) or 200 mA DC,
25 A AC (Feature G01 or SECUTEST SIII+H)) as well as polarity can both be
changed by pressing the or the key.
Testing with 10 A Test Current (Feature G00)
or 25 A (Feature G01 or SECUTEST SIII+H)
The test has a maximum duration of 30 s (fixed value) if 10 A or 25 A test
current is used. After this time period has elapsed, the last measured
value is frozen and “data hold, measurement stopped” appears at the dis-
play. If the test instrument becomes excessively warm, testing cannot be
repeated until after a waiting period of 1 minute. When testing with 10 A or
25 A, the last measurement can be repeated if the test results in failure.
PE
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