On 3/17/2014 6:01 PM, david@righthere... wrote:
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



My suggestion is to learn more about what you are thinking of doing. If
your boat is currently set up for a 30 amp, 120 volt service, there's
more to it than just replacing the plug to get 50 amps.

The 50 amp services are, as you stated, more like the power service to
your house. 240 volts between the hot legs and 120 volts between either
of them and neutral. There's 50 amps available for each of the
distributed legs or a total of 100 amps.

The power panel in a boat designed for a 50 amp service distributes the
two 120 volt legs equally to power the boat's electrical system. Any
240 volt items runs off a double pole breaker. Frankly, I've never seen
a 240 volt appliance on a recreational use boat. Not saying they don't
exist. I've just never seen one. The last boat I had had a 240 volt,
50 amp service. It had a washer and dryer. The dryer ran on 120 volts,
not 240.

The wiring on your 30 amp service is sized from the inlet jack to the
power panel for 30 amps. There should be a 30 amp main breaker in your
power panel that would trip if you draw over 30 amps, so there's no
benefit. If you replace the main breaker in the power panel with a 50
amp breaker, you run a risk of fire due to overloading the wiring
between the power inlet plug and the power panel, so you would need to
replace that wiring with a bigger gauge.

Some boats have *two* 30 amp services and power panels. That might be
an easier way to go if you are trying to add more available amps.