??? upgrading shore power to 50A 220V

Discussion in 'Electrical Systems' started by nopeda, Mar 17, 2014.

  1. nopeda
    Joined: Aug 2013
    Posts: 13
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    Location: GA

    nopeda Junior Member

    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 here:


    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 here:


    Thank you for any help!
  2. daveydavey
    Joined: Mar 2014
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    Location: ON

    daveydavey Junior Member

    Coincidentally, Was VP sales for Hubbell in Canada till recently and spent 20+ years with that stuff...

    That is a 50A twistlock and uses the metal housing for ground. You are correct about the contacts. The 250V refers to the rating, not the voltage on tap. IMO 50A twistlocks are awful - the male housing gets knocked out of round easily, preventing engagement with the female. These are rarely used in industry, there are much better designs. The metal housing is archaic. When last did you see a metal power drill?

    Google Hubbell Marine Products or their competitor Marinco for more appropriate versions with appropriate weather and water protection.

    You can always run 2X30A as well if you plan the boat end well and don't really need 250v.

    Best connector for marine use is a series referred to as IEC 308 style. Watertight, safe and very durable. Next time you are in McDonalds look at the brightly colored connectors used to hook up the fryers, pizza ovens, etc. used for 100A marine service, they are available smaller. Google "Hubbell Marine Pin and Sleeve" to get an idea.

    Not pimping Hubbell, Marinco is another brand that probably has what you want.

    Good luck.

  3. sdowney717
    Joined: Nov 2010
    Posts: 852
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    Location: Newport News VA

    sdowney717 Senior Member

    The ground is on these plugs as part of the outer shell. So no extra wire is needed.
    I have a Y adapter that splits 50 into twin 30 amp power.
    Where I boat I only ever use a single 30 amp.
    My boat is wired up so that all air and water heaters are on one 30 amp line and everything else is on the other. (microwave, fridge, outlets, some lighting)

    I have thought I could join the seperate 30 amp hots on the boat with a toggle to get the heaters running off one 30 AMP LINE. But if plug
    into a regular two phase 250vac line, that would be a direct short, if the switch was turned on.

    I could I suppose rig it as a circuit breaker that would pop open if that ever happened. Interesting idea!

    My interior panel feed lines and wires from the boat sockets are all 8 gauge wire.
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