My favorite topic.
"Rules".
JimL got all huffy when asked him how these "Rules" came into being as it seems a logical question to ask when one considers all the contradictions and disparities cited by so many Posters here.
My ol' Daddy was a Master Electrician and had his own Construction business. One of his favorite comments to young Engineers was "Just because you draw a Mule standing on the Ceiling does not mean I can put him there.".
How many different problems have we listed?
We have comments from the USA, UK, Oz, Spain and where else suggesting all is not well with our various authorities implementation of the "Rules".