a. Set the test function switch to the X5 position and the RCD
rated tripping current switch to 30 mA.
b. Set the 'RCD Test' switch to the 0° position.
c. Press the test button. The RCD should trip and the trip time
in mS will appear on the display. When the breaker trips, the
display will remain visible for approx 10s. To hold the reading,
press and hold down the test button. Note the reading.
d. Reset the RCD.
e Set the 'RCD Test' switch to the 180° position.
f. Repeat the test at c. above. Note the reading.
g. Reset the RCD.
h. Set the 'RCD Test' switch to the 0° position again.
i. Repeat the test at c. above. Note the reading.
The trip times of the two measurements at f. and i. above
should both be less than 40 ms or as specified by the
manufacturer for the particular type of RCD under test. If the
tripping times are greater than 40 ms, it is likely the RCD
is faulty. Carry out further investigations to verify the cause
before replacing the RCD.
5.2.4 Testing DC sensitive RCDs (DC)
This test is designed for RCDs which are sensitive to DC
fault currents. It is primarily designed to test RCDs of 30 mA
sensitivity.
a. Set the RCD rated tripping current switch to the 30 mA
position. Set the function switch to the DC test position.
b. Set the 'RCD Test' switch to the 0° position.
c. Press the test button. The RCD should trip and the trip time
in mS will appear on the display. When the breaker trips, the
display will remain visible for approx 10s. To hold the reading,
press and hold down the test button. Note the reading.
d. Reset the RCD.
e. Set the 'RCD Test' switch to the 180° position.
f. Repeat the test at c. above. Note the reading.
The readings obtained in 5.2.4 c. and 5.2.4 f. should both be
within the trip time specified by the manufacturer of the RCD at
its rated tripping current.
If the breaker does not trip, or the trip time is outside the
limits specified, it is likely the RCD is faulty. Carry out further
investigations to verify the cause before replacing the RCD.
6. Fuse replacement.
Warning! To ensure continued protection, replace fuses
only with the type given in the specifications.
Note: As the fuse forms an integral part of the instrument, only
replace the fuse with the specified type. Using other fuse types
may cause large errors in measurements and the instrument
may not meet its specifications.
6.1 To replace the fuse:
The only fuse which can be replaced by the user is located in
the UK mains test lead.
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