Benning ST 720 Bedienungsanleitung Seite 32

step 2 of 2:
- If the contact current is lower than the admissible limiting value, a
the I symbol.
LEAK
- The overall test is considered to be passed, if "PASS" is shown on the display.
As an alternative:
BENNING ST 720 in battery operating mode (without mains supply):
- Similarly, a
leakage current measurement method) is lower than the admissible limiting value.
- The test is considered to be passed, if "PASS" is shown on the display.
See figure 5:
Note on measuring the contact current in mains operating mode:
- During contact current measurement by means of the direct measurement method, no part
of the test object must have a connection to the earth potential. The test object must be
placed onto an insulated surface. Otherwise, leakage currents to earth might influence the
measuring result.
- Alternatively, the measurement of the contact current I
measurement (max. 30 seconds). Press the key 4 for approx. > 5 seconds to start per-
manent measurement. After 30 seconds, the polarity of the mains voltage will be reversed
automatically ("L/N" - "N/L"). By pressing the key 4 earlier, the mains voltage polarity rever-
sal can be activated manually and by pressing the key 4 again, the measurement can be
stopped.
Note on measuring the insulating resistance for test objects of protection class III:
- Due to the preset limiting value of 2 MΩ for test objects of protection class II, for the testing
of test objects of protection class III it has to be observed that measured values between
the limiting values of 2 MΩ (protection class II) and up to 0.25 MΩ (protection class III) are
indicated with a
evaluated by a competent person.
8.2.3 Cord test
The cord test can be used both for the testing of IEC power cords (device connecting cables
with IEC coupler) and for the testing of cable reels, multiple distributors and extension cables.
8.2.3.1 Testing of IEC power cords (IEC adapter cables)
- Disconnect the plug of the mains connection cable from the socket K of the BEN-
NING ST 720.
- Connect the IEC power cord to be tested to the BENNING ST 720 by means of the IEC con-
nector J.
- Press the key 2 to start the automatic testing procedure.
- The test starts with measuring the protective conductor resistance R
- Depending on whether the value is higher or lower than the limiting value, a
indicated next to the R
The protective conductor resistance depends on the length and cross-section

of the line to be tested. It is possible that the measuring result is acceptable
although the BENNING ST 720 indicates a
- Please refer to Table 1 for typical resistance values of lines.
08/ 2010
will be shown next to the I
T esting of devices of protection class II (shock-proof devices without pro-
tective conductor and with accessible conductive parts) and testing of de-
vices of protection class III (safety extra-low voltage)
next to the R
ISO
symbol.
PE
BENNING ST 720
symbol, if the contact current I
EA
LEAK
symbol. In this case, the measured value has to be
next to the R
will be shown next to
EA
can be carried out as permanent
.
PE
symbol.
PE

(alternative
or a is
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