🚀 go-pugleaf

Someone mentioned, in this thread, that, in USA, white is only used for the
neutral power return.  But there is one exception that I've seen:  Imagine
you have a ceiling light controlled by a wall switch.  And that the powerline
source comes into the ceiling box, and you have a two wire (excluding the 
safety ground) cable running to the switch.  The two wires connected to
the switch.  Two wire cable ("BX", "Romex") only comes with a white wire
and a black wire, in addition to the ground.  So, how to wire the switch,
what color for what?  Usually, what gets done is to make the white wire
to the switch the hot supply, and the black the switched hot.  So, the
light fixture will be supplied with a black (switched hot) and white (neutral)
from the source.  and the hot white going to the switch connected to the
hot black source.  

                 box in ceiling          box on wall
hot black============--------------------- hot white
source                                  switch
neutral white-------   =================== switched black
                   |   |
                 light bulb
                 in ceiling

safety grounds connect all boxes too.

Go to the library and they should have a book on housewiring.  It's just
as easy to do it correctly as to do it wrong.  And if you do it right,
and you neglect to have your work inspected, it's doubtful that they will
ever know you did anything.  

Disclaimer: Don't blame me.