Megger CM500 - Auto Sequence RCD Test

2. Connect to the supply as detailed on the next page.
3. Select the Ramp test using the
I key.
4. Select the RCD type using the
TYPE key.
5. Press and hold the
TEST button.
If the RCD trips, the first displayed result depends upon the
Setting selected.
Setting A: The contact or fault voltage is displayed with the Loop
or earth resistance, trip current and trip resistance available by
pressing the
DISPLAY key.
Setting b: The trip current is displayed with the trip resistance,
contact/fault voltage and loop/earth resistance available by
pressing the
DISPLAY key.
The Trip current and the Trip resistance values are displayed
with both the 0˚ and the 180˚ symbols. The Trip resistance is the
fault required to trip the RCD.
Auto Sequence RCD Test
If the RCD is not located near a convenient installation socket, it
could mean walking back and forward between the RCD and the
instrument to reset the RCD each time it trips out. To simplify and
speed up sequence testing, CM500 can be set to automatically
perform each subsequent test in the sequence each time that the
power is restored. This test depends upon whether
Setting A or
Setting b is selected. The Overcurrent or Fast Trip is 150 mA
if
Setting b is selected, and 5I if Setting A is selected. The
display shows
150 mA or 5I symbols as appropriate.The test
procedure is as follows:-
1. Connect to the supply as detailed on the next page.
2. Select the RCD rated current on the rotary switch.
3. Select Auto RCD test sequence by pressing the I key until
the
1
⁄2I; 0˚; 180˚ and Fast trip symbols are all displayed
together. Auto test is only applicable to a.c. sensitive non
delayed RCDs, therefore
Type segments are not
displayed.
4. Press and release the
TEST button.
5. Reset the RCD within 30 seconds after each trip test.
6. Tests will be carried out in the sequence
1
⁄2I, 0˚, 180˚,
Fast Trip 0˚ and 180˚. After each trip test, CM500 will wait
for up to 30 seconds for the supply to be switched back on
before continuing with the next test. The test sequence will
abort if any of the tests fail, or if the RCD is not reset within
the time limit.
On completion, the result of the last Fast trip test is displayed.
Press the
DISPLAY key to sequentially display:-
- Supply voltage
- Supply Frequency
- Contact/Fault voltage
- Earth Loop/Earth Resistance
- 0˚ trip test time
- 180˚ trip test time
- 0˚ Fast trip test time
- 180˚ Fast trip test time
All results can be stored under a single circuit reference. See
'
Test Result Storage, Deletion and Retrieval'.
Operation (Contd.)
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