I remember reading the C&G examiners report on the July 2008 (I think) exam and the reasons given for the low pass rate was because candidates were getting a lot of the terminology wrong and missing out important information.
One question that let a lot of people down, for example, was "What are the four tests made to verify correct operation of an RCD". A lot of students got three but forgot the fourth - press the test button. (Funnily enough, C&G themselves forgot about 180 degree rotation)
Lots of students, also, could not correctly name the the four pages that make up a EIC. Answers included things like "Test results sheet", "Schedule of Tests and Inspections" and suchlike.
Many students failed to correctly differentiate between earthing conductors and bonding conductors and many used terms like Earth Wire.
Another thing that trips up a people is safe isolation procedures (Check that it is safe to isolate (this catches most out), prove the meter, check the voltage, isolate, recheck the voltage, prove the meter again and lock off). In real life, we may not be so precise.
The devil is most definitely in the detail and learning all the correct terminology is fundamental to success. It's one of the few exams where EVERYTHING has to be by the book. When your other half complains that you were muttering about supplementary bonding in your sleep, you are probably well on the way to passing!
Edit: Found a link to an interesting report
HERE
