Most of the DIY books come with a small fine print warning in them. I honestly believe that if these books did not say shut the power and check for power. A lot of DIYers would kills themselves.
Also there is no way any book on any trade will be 100% correct. Something is always going to slip by the editors.

When was the last time you guys looked at an License Exam book? Did you count the mistakes in it?


when in doubt jump it out
I happily work for slumlords