I have a 2005 code book and what I read is any line to line
equipment shall be rated 208/230 volt.
I suppose 3 phase could be used in a park and you could feed
loadcenters 3 phase 120/208. Not practical...but you could.
However, there is nothing, that I'm aware of, in the Motorhomes that uses line to line voltage. 3 phase..line to neutral is 120 volts.
This is the first time I've been involved with an R.V. park and was told even the Big homes that everything is 120 volts. The bigger 50 amp R.V. plug is just like a range outlet basically except both phase (hot) wires share the neutral...nothing line to line inside the home.
There may be some instances where equipment is used 208/230,
I bet not very often.
