Another question, still related to the connections in a roof/enclosing it blah blah....

Open wiring is legal, not preferable but legal. How do you make joints on open wiring.....by using a porcelain screw. This joint then is not in a box/enclosure?, yet, the term "open wiring" in my view is the entire system, not just the two wires, but everything you would normally use for open wiring. So, open wiring joints are in free air....no enclosure.....although you cannot touch the live part with the STF.....it is in theory legal......therefore I deduce that a joint in a roof can be done with no enclosures as long as you use a porcelain screw??????? Whats wrong with this statement?