Benning ST 720 Bedienungsanleitung Seite 35

- Otherwise, the measurement of the protective conductor resistance (R
automatic polarity reversal and the highest measured value of both measurements will be
shown on the display.
- After the R test has been passed, the test of the protective conductor current I
PE
carried out as permanent measurement for max. 30 seconds. Press the
early the measurement.
- If the protective conductor current is lower than the admissible limiting value, a
shown next to the I
- The overall test is considered to be passed, if "PASS" is shown on the display.
See figure 8:
Note on testing three-phase test objects under operating conditions:
- The protective conductor current measurement will be carried out by means of a current
transformer in the protective conductor of the measuring adapter. The test object must be
placed onto an insulated surface. No part of the test object must have a connection to the
earth potential. Otherwise, leakage currents to earth might influence the measuring result.
- When pressing the key 7 without previously connecting the measuring adapter to the BEN-
NING ST 720, the following warning will be shown on the display:
9. Maintenance
Before opening the BENNING ST 720, make quite sure that it is voltage free!

Electrical danger!
Work on the opened BENNING ST 720 under voltage may be carried out only by skilled electri-
cians with special precautions for the prevention of accidents.
Make the BENNING ST 720 voltage free as follows before opening the instrument:
- Switch the tester off.
08/ 2010
symbol.
LEAK
T esting three-phase test objects under operating conditions (test sample
placed on insulated surface)
BENNING ST 720

) will be started with
PE
will be
LEAK
key 7 to finish
will be
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