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50 amp Shore power

Posted: November 14th, 2024, 9:24 pm
by BTEOTR
Hello just bought our 2008 Carver 41 CMY ( which is now wrapped for the winter) and I don't know what I don't know so please help ;).
We have a single 50 amp male connection at the boat attached to a Y splitter into two 30s. Problem is the boat only works when both are plugged into 2 plugs at the pedestals.
We have a line 1 and line 2 setting on the panel but not sure if that has the ability to make the boat work with only one 30 plugged in and we just regulate power.
Any insight ?

Re: 50 amp Shore power

Posted: November 15th, 2024, 7:07 am
by pepmyster
On our 360, We have 2 cables (30 amp). One says line 1 and the other line 2. On the 120 panel, it is divided line 1 and 2.
line 2 is for all thing AC. It is good that they separated this for sure. I can allow power to either of the 2 ac units. Hopes this helps.

Re: 50 amp Shore power

Posted: November 15th, 2024, 8:02 am
by BTEOTR
Thank you for that. So you have 2-30 amp at the boat not 1-50 ?

Re: 50 amp Shore power

Posted: November 15th, 2024, 8:10 am
by bud37
Welcome to the forum....is this the adaptor you are talking about ? If so it is wired a certain way I believe, see the link. I think midnightsun may have the same set up..

https://www.marinco.com/en/p/RY504-2-30 ... -Males-to#

Re: 50 amp Shore power

Posted: November 15th, 2024, 8:23 am
by Rocketman
The boat is wired for a single 220V - 50 Amp plug. Internally on the boat one side of the 220 is going to line 1 and the other side is going to line 2. You have no way of applying line 1 to the line 2 side.
The adapter is taking each of the 30 amp power and applying to each side of your 50 amp 220 plug.
I doubt your boat actually has anything that is using a true 220V power. It is just an easy way of splitting the load.
As a matter of fact - most have an internal isolator that will not work if only one of your 30 amp plugs is actually plugged in. The isolator is designed to take the 220 power across an isolation transformer to the boat.

Re: 50 amp Shore power

Posted: November 15th, 2024, 7:45 pm
by TheGetaway
I had this same problem this season. It took me a bit to figure out that the power pedestal was only supplying 1 side of the 50 AMP.

Re: 50 amp Shore power

Posted: November 15th, 2024, 10:18 pm
by BTEOTR
Thank you to you all for the feedback, a great place for us all to have for sure.

Rocket man, you say this internal isolator will mean I always need both 30's plugged in for the shore power to work ?

Reason I ask is very few lock stations we have travelled through have 50 amp pedestals so I have been using the splitter with two 30's to make anything and everything to work.
So my fear is some one will show up and complain I am using two plugs and need one or worse yet go ahead and just unplug one without checking with me and cutoff power or worse yet damage something. Any more thoughts ?

Re: 50 amp Shore power

Posted: November 16th, 2024, 7:06 am
by Midnightsun
Welcome and congrats on your new acquisition. Had the same questions and dilemma when we got ours. As mentioned the 50a 250v inlets goes to an isolation transformer where it exits as 2 separate 120v lines feeding your main panel. There really is no way to power the boat from an external source unless you feed it 250v either directly via a 50a receptacle or through 2, 125v (30a standard receptacles) lines on opposite phases into a reverse Y adapter.

This does become an issue when the boat is on the hard. I did install a independent 10a x 4 outlet charger that can be plugged into a standard 125v outlet as this allow me to maintain the batteries while on the hard.

When one has a reverse Y adapter plugged into the pedestal it is obvious it goes to a single 50a cord, nobody will disconnect it.

A quick note on using dual 30a outlets at a marina. You must find the 2 outlets that are on separate phases. In other words these pedestals are set up just like your home panel with 2 separate legs each one its own phase, in order to produce 250v you need to tap into a leg from each side other wise it will not work. The good news is a reverse Y adapter has an indicator light that will only light up if you are plugged into 2 opposing phase legs and you are getting 250v. This means you may need to plug into 2 side by side 30A outlets at the dock or one in the front and one in the back using the indicator light to acknowledge you are correctly plugged in as there is no rule as the how the pedestal is wired.

Sorry about the long rant but this is imperative info you must know or you will be cursing every time you plug in and there is no power.

Re: 50 amp Shore power

Posted: November 16th, 2024, 9:04 am
by BTEOTR
Well good morning and thank you for that. I appreciate you taking the time and all the info was relevant for sure.
You mention "on the hard" good way to put it as we expect to be doing some work in the spring on the hard. It would be nice to have some power.
So do you think the two 30s could be reduced further to 2 regular 110s and just plugged into regular outlets ? I guess again bearing in mind that they also may need to be separated.

Re: 50 amp Shore power

Posted: November 16th, 2024, 10:03 am
by Midnightsun
So do you think the two 30s could be reduced further to 2 regular 110s and just plugged into regular outlets ?



Pretty sure it would work however those 15a 110v outlets would need to be on opposite phases which you will not find on the same outlet and you would be obviously limited on power.

Why do you need 125v power on board while on the hard? Your water supply will function as well as the heads since they are connected to the potable water supply. Lights and radio work fine. Only AC/heat, stove and water heater will be non functional.