I know this is an old thread but a quick question on class 1 power adapters?
After a discussion with a fellow PAT tester in another building -
If you do get a viable earth reading at the "DC" end, even if it's close to the pass/fail limit, do you then plug the adapter into the unit it's supplying and continue the test on that item? which 95% of the time will fail because of the presence of the adapter, one of us said yes the other said just do a visual.
If it helps the item that caused the discussion, was a sound desk with a 5pin DMX.