hooking a 30 amp boat to 50 amps

[zanedclark]

We have a 2000 340 Sundancer. As you know this boat is a 30 amp shore power boat. We are anticipating a trip this fall where we will be required to connect to a 50 amp shore power source. We know that we can purchase a 30 to 50 adapter, but the question is: how will this effect us. Do we need to watch any special precautions?

thanks

zane d clark, california delta to san francisco

 

[vanburen]

The amp rating of shore power reports how much current it can support. Your boat can be sustained by a 30 amp circuit. A 50 amp shorepower connection can provide that much more. If you have the proper adapter so that everything connects, you will be fine and not taking as much as the connection can deliver.

 

[beachcombersc]

Don't rely on the marina to supply this. That thing costs about 130 bucks, and they dont keep many around....

 

[JVM225]

There are two different adapters. I mght have the Marinco numbers reversed but I think the 50/125 is part #110A and the 50/250 is part #121A.
You need to find out from the Marina which type of 50 Amp outlets they have.

 

[Sea Gull]

There will be very few places that supply 120/50. You will mostly find 240/50 service.

 

[Four Suns]

I'll post my ignorance on power again...

Isn't 240V/50A service supplied by two 120 Volt hot wires, a neutral, and a ground? Getting 120 Volt/25 Amp service out of that would be just using one of the hots, the neutral and the ground? Why does that cost 150 bucks for an adapter? Seems like you could just buy a male 240/50 plug and a female 120/30 plug and put about 2 feet of 6/3 wire between them and only hook up one of the hots on the 240 side... am I wrong again? And so... the million dollar question is, does a 50 A breaker trip when one of the hot wires is sucking down more than 25 A or does it trip when both wires are sucking down more than 50 A...? Yeah... probably need some RMS Volt Amp square root of two thing again.

I understand why the adapters to get 240/50 out of 2x 120/30 hookups are expensive because you have to have a box with some smarts in the middle so you don't electricute yourself when you plug the first 120/30 into a plug...

 

[mrsrobinson]

At our last marina all we had were 2 50 amp connections at the dock. We used a single 50 to 2 30 splitter for many months with no issues, at least visible/known issues.

 

[Hampton]

They cost $130 because they have heavy, sealed cords and plugs and, oh yeah, that supply and demand thingy.

 

[aprilfools63]

There are two different adapters. I mght have the Marinco numbers reversed but I think the 50/125 is part #110A and the 50/250 is part #117A.
You need to find out from the Marina which type of 50 Amp outlets they have.

Marinco: http://www.marinco.com/scpt/brandSearches.php?currentMarketName=Marinco%20Shore%20Power&currentSection=Shore%20Power%20Adapters&currentSubsection="Y"%20Adapters
The 50/125 (152AY) goes for $190 @Star Marine
The 50/250 (153AY) goes for $221 @Star Marine

Charles Marine: http://www.charlesindustries.com/main/ma_adapters.html
The 50/125 (A3030Y50) goes for $190 @Boatfix
The 50/125 (A3030Y50H) goes for $171 @Boatfix

I have a set of the Charles Marine A3030Y30 ($122 @boatfix) cables that allow me to connect my two 30 amp cables to a single 30 amp outlet. I have to limit my power usage (no stove or microwave), but they work great and are UL certified.

 

[zanedclark]

thanks for the info!

zane

 

[Sea Gull]

The parts listed by the "fool" above are Y adapters. If you have a single 30 amp connection I think you actually want the 121A.

 

[jg300da]

To answer the original question, with the 121A adaptor Seagull mentions there are no additional precautions or concerns. Just be sure to keep your eye on that adaptor as they like to walk....

 

[aprilfools63]

The parts listed by the "fool" above are Y adapters. If you have a single 30 amp connection I think you actually want the 121A.

I believe that a 2000 340DA has two 30 amp connections, requiring a Y adapter to connect one 50 amp to the two 30 amp shorepower cables.

 

[JVM225]

I just checked the part numbers:
Marinco # 110A is 30 - 50/125 (Still pretty common around here).
Marinco # 121A is 30 - 50/250 (Come across this one too).
I have a 30 amp shore power cord and I carry both of these adapters aboard because I could be in situations where I need one or the other. Nothing worse than backing into a slip on a hot summer day, getting all tied up, then finding out that you don't have what you need to hook up to the electric.

 

[doozie]

To answer Gary's question, the breakers will trip at 50 amps, either hot wire needs to go over 50, Yes you could use 1 on the hot wire, but you still need to buy the 50 amp 125/250v plug, which even for me to buy, I'm an electrical contractor, cost about $ 100.00, so you might as well just buy the premade cord. Bob