OT Voltages

[J. Larry Hendry]

> OT: How the heck did Europe end up with 235V/50Hz anyway? 

Well, as someone who has worked for a US power utility for 22 years, I am
somewhat confused by the discussion of "why" different voltage levels.  I
might more often ask why the different "frequencies."  And, today, the
normal distribution voltage for a US residence is 240 anyhow not 120.  The
difference is that the 240 volt secondary winding is center tapped
providing two legs of 120 volts 180 degrees out of phase.  So the US system
is set up for 120 volt and 240 volt loads with 240 generally reserved for
the larger loads such as electric heating, cooking and clothes drying.  I
suspect you will not find many US homes today with 120 volt services. 
Almost all are 240 volt.

I have a question for some of the UK or other Europe guys.  If your service
is 235 only what is the relationship between each of these conductors and
earth.  Is one leg of your 235 considered a neutral (one leg of 120 is a
neutral in the US). Or, do both legs of the 235 volt supply have potential
above ground (earth)?

Larry Hendry