View Full Version : 50 Amp 240V to 30Amp 125V Adapter

02-24-2007, 09:28 PM
Does anyone have experience taking their 50Amp 240V boat power to a 30Amp 125V shore power outlet? I've tried using a Marinco 30Amp male to 50Amp cord without success. This is on a SR 450.

Also tried a 167RYN adapter - 2 30's to a 50 without success but I believe that problem is due to the shore pedestal being single phase.

Appreciate any suggestions.


02-25-2007, 05:24 AM
Not any help, but I'll be waiting to see if anyone has any advice, because I want to buy an adapter for that as well, if there is such a thing.

02-25-2007, 05:50 AM
If you use a single 30 amp 125v male to a single 50amp 125/250v female you will only energize half of the circuits onboard. which half will depend .....Plus, this is a bad thing if you have any 220 v devices.

What you need is a smart converter. It will be 2 male 30 amp 125v to a single 50 amp 125/250v female. At the dock, you will need to have 2 30amp 125v receptacles that are wired on different phases of the supply. The smart part of this connector will have an LED light to let you know if your supplies are wired correctly.

02-25-2007, 06:56 AM
This maybe is what you need?

http://www0.shopping.com/xPC-3000_Watt_Step_Up_Step_Down_Automatic_Voltage_Regu lator_Transformer

Daniel P Thomas
02-25-2007, 02:42 PM
A friend has a 50amp/240v Gulfstar
He has an adaptor called a 'Smart Y'
That had 2 -30amp connectors to the50amp
But he needed the 30's to usually be on separate pedestals
You might try that

02-25-2007, 03:48 PM
Thanks to all for your suggestions. We'll keep trying and let you know whatever solution we find.

Jacks Racquet - looks like we have the same boats. Maybe we can compare notes on other items.

Thanks again.

02-25-2007, 05:17 PM
It won't matter if the 30amp service comes from two seperate pedestals. The reason is, that the source from each of the 30amp supplies can still be from the same phase. You need two sepearte 30amp supplies from different phases other wise none of the 220V devices will work.

The smart Y is the way to go, but you need two 125V sources on different legs of the supply...

(Hey Frank W...I thinkg got this clear as mud thing down.... :grin:)

02-25-2007, 06:46 PM
so, if you pull into a marina, and the only service available is 30 amp, can you power at least half your stuff, or are you totally screwed?

I don't know how you try to find two different parts of the supply service to reverse phases. There will probably be one pedestal with 2 plugs on it.

Mike - I didn't know there were any other 450EB's on Board. We can start a 450EB thread, which I guess will be just a chatroom. :smt001

We just picked ours up last Friday.

02-25-2007, 07:07 PM
my guess is that a slip wide enough for the likes of your 14' beam will have either twin 30 125v (on sepearte phases) or single 50 125/250v supplies.

I don't know how the 450EB is set up....is it a single 50A 125/250V inlet? If so, then you may want to invest in a Smart Y adapter...but hold on to your wallet...they're not cheap....

Four Suns
02-25-2007, 07:11 PM
I have a smart Y adapter that turns 2 x 30A into a 50A 240v.... very expensive... and I left one behind once... my wife reminds me of it nightly.

I have several power towers on my dock and they are essentially wired for 240v 50A and then they are stepped down for the 110/120v/30A circuits. If you have 2 x 30A plugs on a single tower, it will probably still be good for the smart Y but that depends on how the electricity is distributed to them.

I should also point out that your 450 probably has some things running at 220/240v like the AC and it is very sensitive to voltage drops. The "other" Frank (Just Ducky) had a good write up on voltage isolators on these boats.... wish he was here to explain.... but.... without "full juice", things will just not work right.

02-25-2007, 07:19 PM
I saw one of those smart y's by hubbell. haven't heard of hubbel before, but it wasn't too expensive. about $300. is something like that what you had? the marinco's were something like $700.

Four Suns
02-25-2007, 07:20 PM
yeah... I have the Marinco stuff... have not heard of the other company.

02-25-2007, 07:53 PM
hubbell has been around forever (since i was a kid). i have some of their stuff but the marinco is better quality.

is there a reason why larger boats now feature the single 50amp receptacle as opposed to the twin 30amp? it is so much more complicated and expensive. two 30amp 50' cables will run around $120, while the single 50amp costs 4x that. the Y adapter to convert 50amp at the dock to twin 30s costs about $180 and the "smart Y" costs 30% more :huh:

this is what west marine sells:

boaters world gets $50 more

Four Suns
02-25-2007, 08:22 PM
The bigger boats are 240v/50A. I guess they could put the "smart Y" electronics in the boat and have 2 cords but it is not going to save much money. Having a single 240v/50A is better than two cords....

02-25-2007, 09:24 PM
Our boat needs 240V - 50 amp- We have a power isolation boost box also to keep the electronics from brownout. We need 50 amp, and once in awhile we will go to a Marina that only has one 30 amp., Our boat will only powerup if we run a power cord down several docks to get in the proper phase as mentioned earlier. So along with the other adapters we carry extra 30 amp cords. Hook that up with a 30 amp. y-spliter so the dock we are taking power from can still get power (off of our splitter at their dock. If someone wants to be not-so-nice, I just let them know that my genny is pretty loud all night long. One 30 amp only means -
Genny on all the time!

02-26-2007, 08:54 AM
RE: "why do they use 50 amp cords vs two 30 amp cords?" Basiclly, a 240 V 50 cord set brings 100 amps to the boat. Twin 30's only would bring 60 amps.

Sea Gull
02-26-2007, 11:27 AM
Marinco, Hubbel and Charles all make a device to do this.

Best prices I have seen (since I also need one for the new boat) are:

Marinco 167RYN $318
Hubbel YQ230 $309
Charles 93-SMTY 50W-A $261

They are also sometimes available on E-Bay if you like shopping there.

02-26-2007, 02:39 PM
RE: "why do they use 50 amp cords vs two 30 amp cords?" Basiclly, a 240 V 50 cord set brings 100 amps to the boat. Twin 30's only would bring 60 amps.

That's a good point...keep in mind, that if you use a smart Y, you will not have the maximum current of 100amps available. Again, I am not familiar with the 450 wiring, but I assume (I know..I know) that they sized it that way for a reason. One side of your on board 120V could draw more than 30amps ( hair dryer,iron,HWH, one of the AC unit, frudge, icemaker, the girls straightenrs, etc) at one time and pop a breaker on one leg of the 30 amp supply. Not a big deal, unless you also have some sensitive 220V stuff that doesn't like to see only 120V.......when you are on the smart Y system, you will have to monitor your on board amp meters a little closer, and budget your current draw each side.

03-14-2007, 09:51 PM
How come I never see a thread on the virtues of 60 amps vs. 100 amps shore power draw on the sailbote forums? :grin:
(Yes, I'm a Son of a Son of a Sailor)

03-14-2007, 10:00 PM
do they even use electricity on snail-bloats?? i thought maybe they'd have a wind turbine set up, or maybe use the movement of the ocean currents to power their coffee makers.

04-22-2007, 07:41 PM
Operating with an open leg is in my opinion dangerous. Given the 240 loads and the 110's the system draw is never balanced and breakers are going to be snapping constantly besides wiring over heating.

The expense of a Y adapter is the safe solution, even if you have to get a dumb one you'll be better off and so will your boat.

Just my 2cents