30A or 50A?

[saltshaker]

BTW, if you split 50A 250V don't you end up with 2 25A legs?

You can split it to get 2 50A 125V feeds or use it for the single 50A 250V feed. If you wanted 2 250V feeds then yes you'd end up with 2 feeds totaling 50A. The 50/250 gives you 2 50A 125V legs. You get the 250V when you combine them.

 

[34Hatt]

You can split it to get 2 50A 125V feeds or use it for the single 50A 250V feed. If you wanted 2 250V feeds then yes you'd end up with 2 feeds totaling 50A. The 50/250 gives you 2 50A 125V legs. You get the 250V when you combine them.

Yeah who said anything about splitting and getting two 25. 50 amp at 120 you need to just use it that way but I know you knew that already. Cruising and finding 250v 50amp for OUR SIZE BOATS is not easy. All the slips I have been in around here is 120 volt twin 30amp or single 50 amp which I use a splitter for my two 30's.
They have slip with 220v 50 amp but are for larger boats and they don't like putting a 36' in a slip meant for a 40's +++

So I have to agree with are you sure you want to do all this with old parts?

If you do I have my old panel that has the hatteras gauges in Nice shape if you want them they are yours since I still owe you at least one favor

Maybe make one nice twin 30 amp with dual volt and amp gauges?

 

[Avenger]

50 amp at 120 you need to just use it that way but I know you knew that already. Cruising and finding 250v 50amp for OUR SIZE BOATS is not easy. All the slips I have been in around here is 120 volt twin 30amp or single 50 amp which I use a splitter for my two 30's.
They have slip with 220v 50 amp but are for larger boats and they don't like putting a 36' in a slip meant for a 40's +++

Exactly why I'm not excited about the 250V setup. If I had 250V Air Cond it would make sense from the generator and shorepower side, but then if there's no 250V shorepower available I'm either sweating or annoying the neighbors with the generator.

So, for the electricans here, how do we get two legs of 50A 125V out of 50A 250V? Doesn't that require the neutral to carry 100A?

 

[RT46]

you can use a 3 way splitter that has one male 50A/250v and two female 50A/125v

they are around $300-400

 

[saltshaker]

Exactly why I'm not excited about the 250V setup. If I had 250V Air Cond it would make sense from the generator and shorepower side, but then if there's no 250V shorepower available I'm either sweating or annoying the neighbors with the generator.

So, for the electricans here, how do we get two legs of 50A 125V out of 50A 250V? Doesn't that require the neutral to carry 100A?

Standard 50A/250V shore power has 2 125V hot leads and one neutral that both use. You only get the 250V when you combine the 2 hots. If you want 2 50A 125V services all you do is use one hot for each panel. I did exactly what you're trying to do on my 46C except I already had the 2 50A 125. I converted my inlet to a 50/250 to eliminate a second cord and because 50/125 is hard to find. I've never run into a problem finding 50/250 even when I had my 36 Trojan. Most pedestals will have both 50/250 and 2 30/125

 

[Avenger]

I'm pretty sure either way both panels will wind up with a 50A service of some kind. It just remains to be seen what configuration. It will probably be the one which ends up with the least number of adapters. If 50A 125/250 service is that common a single connector makes sense.

Now back to the 50A question. If you have 2 separate legs of 50A 125V each connected to the same neutral, isn't that neutral carrying 100A?

Actually, if you convert the power into watts it all adds up until you look at single 50A 125V code which calls for the same gauge wire as the 125/250. In theory, you should be able to pull 100A 125V through that.

 

[saltshaker]

The neutral will never carry more than 50A so you'll never get more than a single 50/250 or 2 separate 50/125. Looking back on my previous post, I need to clarify a few things. First the proper service at the marina will be 50A 125/250V. There are 2 hots carrying 125V each, 1 neutral and 1 ground. You can get 2 50A 125V services by using the hots individually and splitting the neutral. If you want 50/250 you use the 2 hot legs and no neutral. The 2 hots are opposing phase so that's how you get the 250V. If they were the same phase, you'd get nothing by using the 2 together. Hope this clears things up and sorry if I caused any confusion.

 

[Avenger]

I understand how the 250 with two hot legs is achieved vs. two separate legs of 125. The question is, how do you get 50A from each of those two 125 legs without putting 100A through the shared neutral? Alternating phases cancel each other out?

 

[saltshaker]

The neutral will carry the balance of the load each leg is using but never more than 50A total. Look at the 2 legs as being completely separate unless you use them together without the neutral. It's a simple set up given what you have. You'll get 50 125 to each panel but no 250V unless you add a 250V panel. You probably will need to run new wire from the inlet to each panel as your existing service was only 30A each. Mine were already 50A 125V so all I was changing was the inlet and the cord.

 

[RT46]

If you have 50A/250v on the dock

you can easily make that into two 50A/125v for the boat

there is a three way splitter sold just for that purpose

(50A/250v makes two legs of 50A/125v because each hot (there are 2) on the 250v side carries 50A)

that is the way my boat is set up.

 

[Avenger]

We're getting way off track here.

I was just trying to see if someone knew the electrical theory behind why it works the way it does. Obviously it does work, otherwise the neutral would have to be much larger in a four wire system. I was just wondering how you can get 50A from each leg of a system without putting 50 amps from each leg through the neutral. Circuit being a circuit and all.

It looks to me like the neutral is seeing 250V when both legs are connected to it. So it's back down to 50A which is why the wire doesn't melt. As I said, if you convert to Watts it all evens out.

 

[saltshaker]

It's the same as in your house. Only difference is at the dock you need to run a ground wire to connect the boat. You do not need any adapters once you do this. The nice advantage of keeping the two panels 125V is you can easily make a reverse Y that will allow you to plug in to 2 30A 125V outlets and power everything on the boat. I also had a single 30A to 50A adapter that allowed me to run the entire boat from one 30A outlet. Comes in handy when you're on the hard or only have a standard Edison outlet. Of course you would also need a 30A to 15A adapter but you get the idea.

 

[Avenger]

I already have a 30 to 15 adapter.

It is starting to look like 50A 125/250 is a good option. Less cable, less adapters in general but the option to adapt to 30A in a pinch and future flexibility in the unlikely event I want to go to 250V. Plus one of our members suggested an option for circuit breakers that could use a former 30A spot if I go to a single connection.

Great ideas from everybody. Thanks as always for all the input and discussion.

Anybody want to buy some new 30A shorepower inlets?