Amprobe MEGATEST-1000 Megohmmeter - Manual (Page 10)

5. SWITCH POSITION FUNCTIONS:
5.1 “LOW Ω” POSITION
5.1.1 CONTINUITY TEST:
Continuity test of earth, protective and equalizing potential conductors with a test current
higher than 200 mA and open circuit voltage ranging from 4v TO 24v
o
WARNING:
Before carrying out the continuity test make sure that there is no
voltage at the ends of the conductor under test.
Turn the switch on LOW Ω position.
The key FUNC permits to select one of the following measuring modes
(which can be shown cyclically when pressing this key):
FUNC
Mode “AUTO” (the instrument carries out two measurements with
reversed polarity and displays their average value). This mode is
recommended for the continuity test.
Mode “R +” (measurement with positive polarity, black cable connected
to positive polarity and blue cable connected to negative polarity). This
mode can be used to evaluate the galvanic effect occurring at the ends
of the installation cable terminals (they are usually made of galvanised
iron) during the continuity test.
Mode “ R -“ (measurement with negative polarity, black cable connected
to negative polarity and blue cable connected to positive polarity). This
mode can be used to evaluate the galvanic effect occurring at the ends
of the installation cable terminals (they are usually made of galvanised
iron) during the continuity test reversing polarity with respect to the
previous mode (R+).
Mode “R + TIMER (measurement with positive polarity and possibility of
setting the duration time of the test). In this case the operator can set a
measuring time long enough to permit him to move the protective
conductors while the instrument is carrying out the test so detecting any
bad connection.
Mode “R - TIMER” (measurement with negative polarity and possibility of
setting the duration time of the test). In this case the operator can set a
measuring time long enough to permit him to move the protective
conductors while the instrument is carrying out the test so detecting any
bad connection.
Mode “CAL” (compensation of the resistance of the cables used for the
measurement).
Note: If the resistance is lower than 16 Ω (including the resistance of the calibration
results) the continuity test is made by the instrument with a current higher than
200mA. If the resistance is higher than 16
Ω the continuity test is made by the
instrument using a current of 40mA.
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