Originally Posted by Shakey

sory mate think you have got a bit confused with your numbers, there is no 2392-20

the 2392-10 focuses on initial verification
The 2391-10 focuses on Periodic Inspection

Its got nothing to do with domestic or three phase

esentially with 2392-10 you can test and verify your own work, with 2391-10 you can test other peoples work

i been teaching 2392-10 for awhile (and 2391), and it is a LOT easier than the 2391 for students!

thanks for the wbsite info