2391-101 Inspection, Testing and Certification of Electrical Installations Testing of a 30mA RCD

The chief examiner for the City & Guilds mentions that many taking the examination fail on this question. Again I have not passed or taken the course but would be tempted to write my answer something like this:

Using a RCD tester that is in calibration, set the instrument to 50% of the tripping current of 30mA, namely 15mA.
Carry out the test at this current for 2 seconds during which time the RCD should not trip for each half cycle.
Set the RCD tester to 30mA (the actual tripping current) and operate the test button. Record the time in mS that the RCD took to trip. This from memory should be less than 200ms if not used as protection against indirect contact, do this for each half cycle.
Where the RCD is used for protection against indirect contact set the level to 5 times the trip current, namely 150mA. On both half cycles the time to trip should be less than 40ms.
Press the test button on the RCD to verify that this functions correctly.