My name is Christian and I am the Proprietor of a PAT Testing firm in Ireland called VINDICO. Our requirements for PAT are broadly speaking the same as those in the UK so I think I may be able to give you some guidance on your query.
Portable Appliance Tests that are mandatory:
Leakage (sometimes referred to as a functional check) is deemed as a good practice test and is used mainly for appliances that have heating elements and motors. On occasion the leakage test can be used as an alternative to the insulation test. An example of this would be for appliances that have surge protectors / suppressors/ filters that may cause the insulation test to fail due to the 500VDC. The two options available here are
1) A reduced voltage of 250V Insulation test can be perfomed
2) A leakage test can be perfomed in place of insulation.
You can see why the leakage test is added as an option on manual PAT Testers and incl into the test sequence on memory PAT Testers. (it’s a backup to the insulation test).
When testing I.T class 1 the earth bond test should always be conducted at 100mA as opposed to 25amps.This is important when testing computers.
Another issue when testing I.T is insulation. Some people feel uncomfortable testing I.T at 500VDC. If you do feel uncomfortable testing I.T at 500VDC you can always conduct this test at 250VDC.
I hope this answers your query.
If you want more information please feel free to check out our website www.vindico.ie.