I have received a reply from Hewlett Packard Ltd helpdesk, which details the 'In Service (PAT) Testing' method for the correct testing of the AC Adapters associated with HP Laptops/Notebooks.
The author of the guideline is Mr Peter Knight, Technical Regulations Manager UK, Hewlett-Packard Ltd., Cain Road, Bracknell, Berkshire, RG12 1HN. Tel: 01344363423, email: email@example.com
I asked if I could share the guideline with you all, but Peter Knight would like to keep the information controlled for the use of HP customers only, and not used to apply to other manufactures products.
You could have a word with Peter if you are involved with HP products & I'm sure he would assist, he was very helpful to me.