I've been on 30A 120V power at the dock for years and would now like to upgrade
to 50A 220V, or what they refer to as 50A 250V at the marina office. I haven't
put a meter on it yet but so far suspect it's closer to 220 than 250. The socket
on the pedestal is like the one pictured he

http://www.catagle.com/68-153/CWD_Ar...uyersGuide.htm

They say it's 3-pole 4-wire. I'm guessing X and Y are the two hot legs and W is
the neutral. Between X or Y and W would be 120V+/- and between X and Y is the
220/250V. Right? How does the ground tie into it though? With only 3 poles do we
run a separate wire from the boat to the pedestal, and if so how do we tie in?

Also can anyone suggest the cheapest place to get a plug like that? So far the
best price I've found is $68.18 he

http://www.ktool.net/servlet/the-581...-63CR65/Detail

Thank you for any help!
David