13.1.7 The 5 x I test
For this test, the instrument uses a current equal to five times the nominal rating (5 x I) of the RCD under test.
The RCD should trip within 40 ms. When the RCD trips the test stops and the instrument shows the actual trip time.
If the RCD fails to trip, the test stops after 40 ms, and the display shows >40 ms.
13.1.8 The ramp test
This test is not usually included in the national and international standards for RCD testing, but it is useful for
investigating ‘nuisance tripping’, where the RCD sometimes trips for no obvious reason. For the ramp test, the
instrument initially applies a test current equal to half of the rating of the RCD (or less) then steadily increases this
current up to a maximum of 1.1 times (110%) the rating of the RCD. During the test, the current is shown as a
percentage on an analogue arc in the main area of the display. If the breaker trips during the test, the current at
which it tripped is shown in the main area of the display. If the breaker does not trip, the test stops when the current
reaches 110%, the pointer on the analogue arc stops at 110%, and the main display shows greater than a value
equal to 1.1 x the rating of the RCD. For example, if you are testing a 30 mA RCD and it fails to trip, at the end of
the test the main display will show >33 mA.
13.1.9 Testing at 0º and 180º
All the RCD and RDC tests can be carried out at either 0º or 180º. If you select the 0º option, the test starts when the
load current is going positive and if you select the 180º option the test starts when load current is going negative.
Some RCDs may give different results at 0º and 180º so it is advisable to perform both options. If you have selected
automatic testing, the instrument automatically repeats the tests at 0º and 180º, unless this feature has been turned
off in set up, Refer to 15.9.7 Auto sequence customisation on page 87.
NOTE : For RDCs the correct terms would be positive (+ve) and (-ve). However as they are usually tested in
sequence following a Type A RCD test, for simplicity the display shows 0º and 180º.
13.1.10 RCD testing inhibit
The instrument inhibits testing if the touch voltage is, or is predicted to be, higher than 50 V.
Testing is also inhibited if the supply voltage is outside the acceptable range (45 V AC to 280 V AC for nominal
230 V supplies and 376 V AC to 550 V AC for nominal 400 V AC supplies), or if the supply frequency is outside the
acceptable frequency range (45 Hz to 65 Hz for nominal 50 Hz supplies).
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Residual current device (RCD) testing
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