Shore power newbie question

Hi everyone, I have a 50amp connection on my boat. Do most marinas have both 30amp and 50amp? If not, do you carry with you a converter from 50amp to 30amp? Not sure how this all works.

Also, everyone at my marina goes bow first into the slips as the front of the slips have angular sections that limit width (but bow fits nicely into front of slip). And of course the power connection is at the front so I'll need to get a 50' 50amp cord. Or would you get a less expensive 30amp cord and convert it to the 50amp connector at the dock using a converter.

Sorry, totally confused.

Thanks,
Mike

If your boat is 50A, and the shore outlet is 50A, then it's important to only use a 50A cord. Otherwise you will overload the 30A cord.

But that's probably moot because most likely your 50A boat is 120/240 volt? If that's the case, the easiest thing is to plug into 50A outlets which are generally available in the US. Just ask the marina ahead of time if they don't ask you first.

If the marina only has 30A service (which is all 120V, not 240V), then you would need what's called a Reverse-Y adapter. They are expensive - around $700. You 50A boat cord plugs into the adapter, the the adapter has two 30A plugs that you plug into two separate 30A outlets on the dock. This will give you 240V, but it will be limited to 30A, not 50A, so you might have to manage your loads a but. The Reverse-Y adapters can be tricky too. The two 30A plugs need to be plugged into 30A outlets that are on opposite phased of a 240V circuit. Most people don't even know what that means, and honestly shouldn't need to, but it is what it is. There is no way to tell if two 30A outlets are on opposite phases other than to plug in an try it. The Reverse-Y has smarts in it to detect whether things are plugged in correctly, and will only turn on if they are. There is usually a little red light that will light up when things are working. So just be prepared to possibly plug into a few outlets to get it to work.

But all that said, I've had very little trouble finding 50A power. The only exceptions have been up the St Lawrence in the Canadian Maritimes. I think that's the only place I used our reverse-Y.

On, one other trick to the reverse-Y. I found places where the two 30A outlets were not next to each other, and the cords on the adapter are maybe 3' long. Carrying a 25' or 50' 30A extension cord can save the day and allow you to reach the other outlet.

Shore power and adaptors

I have, on board, about every adapter possible. My permanent slip has a dedicated 50A 120/240 power cord. I do not remove it when I travel. I have 3-30A 120V 50' power cords that I use when traveling away from home dock. My boat is flexible, wired with a single 30A inlet that will feed both line 1 & 2 at the boat power panel & a 50A 120/240 inlet that utilizes the dual 120v to feed line 1 & 2. I cannot run all powered items from the single 30A inlet and must be selective. Many of the marinas have both a 30A and 50A available at the slip power box. I use a 50A to dual 30A at the dock power box, run 2 - 30A cords to the boat that has dual 30A to 50A boat side adapter. I am sure many will disagree about having multiple adapters but it comes down to shore cord weight and cost. If you have ever handled a 50' 50A power cord or had to replace $$ cord ends, you will know what I mean. I do check my cord ends regularly and use lock rings. If the marina only has 30A 120V I can use one of the cords, no adapters. I have had to put 2 of the 30A (100') together to get to a power connector. In addition to adapters mentioned above, I have a 15A to 30A adapter, 30A to 15A, RV 50A to a 30A and 50A, 50A to 30A, 30A to 50A, 50A 120V to 30A. At one time or another, I have used all but the RV 50A to 50A. The more developed cruising areas reduce the need for "special" adapters. Your needs may be very different.

I have a "pigtail" adapter that attaches to my 50a cord and plugs into a 30a outlet. I have to manage the load when I use it, but it works fine and costs less than a Y adapter.

I have 50 amp service on my boat, and find slips with that power 90% of the time.

Also have the smart box that combines to 30 amp outlets . As mentioned, the outlets need to be on different phases. They will not work on 208 volts, only on 220/240.

Also have an adapter that combines the 2 power legs into one 30 amp plug. Before buying one of these, confirm you don't have any 220 volt appliances (stove, air conditioner, water heater, battery charger, etc.) on your boat.

Also have the same adapter as above to one 15 amp plug. Use this mostly in the boat yard where 30 and 50 amp plugs aren't common.

Ted

If you intend to cruise to different parts of the country and different marinas, you should get the required adapters. Some marinas will loan you an adapter but you can't count on it.

In 18 years of cruising I have used every adapter sold and had to make a couple no one thought of.

Most unusual configurations have been on US canals and in small rural towns. I have run across RV and dryer style outlets. Outside of the US and Canada I have seen bizarre plugs. Once had to hardwire.

Of course in the European countries the adapters for North American power are all home made.

Thus you need a 30 shore to 50 boat, a smart Y, as well as a 15 shore to 30 boat.

"Hi everyone, I have a 50amp connection on my boat."


Hello Michael,
Is your 50 amp connection 50/125 or is it 50/250?
Look at they connector pattern and see which it is so you have a good starting point.

No, not all slips have 50A connectors on the tower. The marina I was in for 6 years didn't have any. The one I'm in now only has them on the large slips. The 25 ft, 30 ft, and 35 ft slips only have 2 x 30A.

You're best bet is to verify what the power options are at the slip when you speak with the dock master or marina management.

smitty477 said:

"Hi everyone, I have a 50amp connection on my boat."


Hello Michael,
Is your 50 amp connection 50/125 or is it 50/250?
Look at they connector pattern and see which it is so you have a good starting point.

Click to expand...

+1

My boat has a 50/125 connection (even though it only has a 30/125 service). My marina happens to have a 50/125 outlet at the pedestal. These are very rare in my area, most are 30 amp with the occasional 50/240 outlets.

As others have mentioned, you will need to get a whole host of relatively expensive adapters to meet your different needs.

The 50/125 are antiques from about 1960,

If anyone needs a plug let me know.

smitty477 said:

"Is your 50 amp connection 50/125 or is it 50/250?

Click to expand...

Not sure. I will check when I get to the boat.

Do most people leave their shore power cord at their home slip, or take it with them all the time?

Obviously, if they left it at their home slip all the time the assumption would be that they have an extra one they keep on the boat.

MichaelB1969 said:

Not sure. I will check when I get to the boat.

Do most people leave their shore power cord at their home slip, or take it with them all the time?

Obviously, if they left it at their home slip all the time the assumption would be that they have an extra one they keep on the boat.

Click to expand...

I take my cords with me. Whatever you own, you might need and unless your home slip is a private one behind your dock, someone might steal them. Besides, they last longer if you keep them out of the light and weather.


I once had to run a 40' and a 50' cord end to end to reach a dock outlet.

I much prefer to permanently leave on on the dock. It means that much less plugging and unplugging from the shore power pedestal with corresponding less wear. I also usually end up using a small line to tie the power cord firmly to the pedestal since over time they don't tend to fit as tightly as they would have when new.

Since I have a 50/125 pedestal and boat plugs, I have a 25' 50/125W shore power cord that I leave on the dock. On the boat I keep a 30amp cord and all the adapters.

dhays said:

I much prefer to permanently leave on on the dock. It means that much less plugging and unplugging from the shore power pedestal with corresponding less wear. I also usually end up using a small line to tie the power cord firmly to the pedestal since over time they don't tend to fit as tightly as they would have when new.

Since I have a 50/125 pedestal and boat plugs, I have a 25' 50/125W shore power cord that I leave on the dock. On the boat I keep a 30amp cord and all the adapters.

Click to expand...

I am probably going to need a 75' cord, so would be a whole lot easier to leave it on the dock, especially since I already have a 25' 50amp cord that came with the boat. Unfortunately, the plug is on the completely opposite end of the boat so it has to go at least 44 feet, plus the width of the beam, which is almost 14 feet.

Is it advisable to string 2 cords together? If so, then I could leave a 50' plugged in at the slip, and use my 25' cord to go the last mile if you will. Then I can simply unplug the 25' and take with, which is a whole lot lighter than a 75' cord would be.

MichaelB1969 said:

I am probably going to need a 75' cord, so would be a whole lot easier to leave it on the dock, especially since I already have a 25' 50amp cord that came with the boat. Unfortunately, the plug is on the completely opposite end of the boat so it has to go at least 44 feet, plus the width of the beam, which is almost 14 feet.

Is it advisable to string 2 cords together? If so, then I could leave a 50' plugged in at the slip, and use my 25' cord to go the last mile if you will. Then I can simply unplug the 25' and take with, which is a whole lot lighter than a 75' cord would be.

Click to expand...

I would recommend taking a 50' cord with you to other marinas. You may find 25' too short. I'd rather be able to dock the boat the way I want to and have to handle a heavy 50' cord, rather than have to dock her a specific way to be able to use a lighter 25' cord.

in addition to the 50/240 connection, my boat also has 2 30/125 connections that allow me to power everything except my 240V systems (heat/ac and washer/dryer). I carry 2 50' 30/125 cables on board as well as multiple adapters. I'm lucky that they came with the boat and that I have plenty of room to stow them.

Richard

Britannia said:

I would recommend taking a 50' cord with you to other marinas. You may find 25' too short. I'd rather be able to dock the boat the way I want to and have to handle a heavy 50' cord, rather than have to dock her a specific way to be able to use a lighter 25' cord.

in addition to the 50/240 connection, my boat also has 2 30/125 connections that allow me to power everything except my 240V systems (heat/ac and washer/dryer). I carry 2 50' 30/125 cables on board as well as multiple adapters. I'm lucky that they came with the boat and that I have plenty of room to stow them.

Richard

Click to expand...

Good points. I suppose I could just leave my longer cord at the marina when I am planning on cruising around the Bay, and take it when I plan on taking a trip.

MichaelB1969 said:

Not sure. I will check when I get to the boat.

Do most people leave their shore power cord at their home slip, or take it with them all the time?

Obviously, if they left it at their home slip all the time the assumption would be that they have an extra one they keep on the boat.

Click to expand...

We have one 50' cord we leave at our home slip, permanently wrapped around the pedestal and a mid-ship pile en route to the boat... so leaving/returning is very simple, takes only minutes. (50A cords are pretty heavy, BTW.) Same with dock lines; home lines stay, pre-adjusted, and traveling lines go with us.

Then we also have two cords on board. One is about 65' on the Cablemaster, usually only a little bit of that extracted from it's garage for connection at home... but then extended (however far) when we're someplace else. The second is another 50' that we can use should we need to extend past the normal 65' cord.

-Chris

MichaelB1969 said:

............ Is it advisable to string 2 cords together? .....................

Click to expand...

No, it is not but sometimes you have to do what you have to do.

It is advisable to use a shore power cord that's as short as practical because the longer the cord, the more voltage drop to the boat under heavy loads like heat or air conditioning.

Sometimes your cord won't reach and in that case, you have little choice but to connect two together.

Michael

If you are going to need a 75 ft cord at your home slip I suggest you talk to a marine electrician about a second shore power inlet on you boat so you can use a shorter cord.

Bay Pelican said:

Michael

If you are going to need a 75 ft cord at your home slip I suggest you talk to a marine electrician about a second shore power inlet on you boat so you can use a shorter cord.

Click to expand...

+1

Bay Pelican said:

Michael

If you are going to need a 75 ft cord at your home slip I suggest you talk to a marine electrician about a second shore power inlet on you boat so you can use a shorter cord.

Click to expand...

Great idea. Thx.

When I had my sailboat in the slip that my trawler is in now I had to use 2 50' cords to reach the power inlet in the stern. It is not a good idea if you can help it, but as others have said sometimes you don't have a choice.

You can get a connecting ring that will provide a solid connection between the two cords and I would strongly recommend some dialectic grease to protect it. I would also suggest that you secure the two cords to you dock and NOT mess with the connection to the dock pedestal or the connection between the two cords.

Mixed supply. Recommend 50 amp cord with 30 and adapter.

My slip has two 30 amp outlets. How do you know if they are on alternate phases?
Plug in two shore power cords and measure the volts hot to hot between both cords?

There are no 50 amp receptacles at this marina.

My slip has two 30 amp outlets. How do you know if they are on alternate phases?

Purchase a cheapo volt meter.

Use the meter in each socket to measure the voltage between hot and neutral.

Should see 120V.

When you figure out which are the hot lines , measure them between the 2 sockets.

IF you see 240V you gave that voltage available , probably only 30A worth tho.

FF said:

My slip has two 30 amp outlets. How do you know if they are on alternate phases?

Purchase a cheapo volt meter.

Use the meter in each socket to measure the voltage between hot and neutral.

Should see 120V.

When you figure out which are the hot lines , measure them between the 2 sockets.

IF you see 240V you gave that voltage available , probably only 30A worth tho.

Click to expand...

Will try that. Meter probes, wish they were longer. I tested the outlets simply for power when I moved to new marina, and took some fiddling to get a reading. Perhaps if I stuck in some long skinny nails will be easier to connect the probes.

FF said:

My slip has two 30 amp outlets. How do you know if they are on alternate phases?

Purchase a cheapo volt meter.

Use the meter in each socket to measure the voltage between hot and neutral.

Should see 120V.

When you figure out which are the hot lines , measure them between the 2 sockets.

IF you see 240V you gave that voltage available , probably only 30A worth tho.

Click to expand...

Right. And if you measure 208V then you have picked up two legs of a three phase system.

I don't know if a reverse-Y will activate if you have 2 legs of a three phase system as opposed to the two legs of a split phase system.

Anyone know?

FF said:

My slip has two 30 amp outlets. How do you know if they are on alternate phases?

Purchase a cheapo volt meter.

Use the meter in each socket to measure the voltage between hot and neutral.

Should see 120V.

When you figure out which are the hot lines , measure them between the 2 sockets.

IF you see 240V you gave that voltage available , probably only 30A worth tho.

Click to expand...

I absolutely would not recommend trying to get 240 from this setup over any length of time. There's no guarantee that someone swapping a breaker or other wiring change won't put them back on the same leg

MichaelB1969 said:

Do most people leave their shore power cord at their home slip, or take it with them all the time?

Click to expand...

I leave it at my slip and Only take it when I'm going to a place where I can plug in (Rare as we anchor out a lot..)....