Shore power adapters

O C Diver · Sep 5, 2015

Multiple parts to this question:

I have seen the following receptacles of 50 amps or less on power pedestals in my limited cruising in North America:
15 amp 125 volt (not twist lock)
30 amp 125 volt
50 amp 125/250 volt

How common are the following that I've seen listed in adapter catalogs?
20 amp 125 volt (twist lock)
50 amp 125 volt
16 amp 230 volt
32 amp 230 volt

If you plan or do extended cruising, what do you carry for shore power adapters? As an example, I have a 50 amp 125/250 volt shore power connection. I also carry an adapter that takes two 30 amp 125 volt receptacles and plugs into my shore power cord giving me 30 amps 125/250 volt.

If you have a 50 amp 125/250 volt cord, but no 220 volt equipment in your boat, would you have an adapter that would take one 30 amp 125 volt plug and power all of your panel. They make such an adapter but it obviously won't power 220 volt equipment.

Have 3 friends with boats but no gensets that I will do some short cruises with. Have run a dedicated 110 volt 25 amp circuit to the veranda that I plan to put a shore power receptacle on for their use when we raft up. You can tap into my genset, but go sleep on your own boat. While 30 amp 125 volt receptacle would be the logical choice, 50 amp receptacles seem substantially more robust. Wondering if cruisers with 50 amp service carry adapters to 30 amp receptacles and the vise versa?

Ted

Bay Pelican · Sep 5, 2015

In the United States in Canada you will rarely see the 20 amp twist lock or the 125 volt 50 amp outlets. The 16 amp and 32 amp outlets are European power outlets which generally do not, cannot exist here. The exception would be a specialty marina catering to European boats that has a separate power supply for European 220v. If you go to the Caribbean you will find marinas with dual power supplies, one for North Americans, the other for the rest of the world. In these cases you will find both types of plugs although almost always at different docks.

ranger58sb · Sep 5, 2015

O C Diver said:
If you have a 50 amp 125/250 volt cord, but no 220 volt equipment in your boat, would you have an adapter that would take one 30 amp 125 volt plug and power all of your panel. They make such an adapter but it obviously won't power 220 volt equipment.

We have a 50A/250V boat. but no 220V systems on board. Main power goes to a split panel, 110V each side, systems (charger, fridges, ACs, water heater, microwave, outlets, etc.) distributed per side semi-equally.

I have two basic adapters, one is a "Smart Y" -- twin-30s-to-single-50 -- and that gets us approx. 30A per leg. We can run most stuff simultaneously, but I think not all. Haven't ever had to test total capacity.

The other is a simple 30-to-50 pigtail. I'm guessing, but don't know for sure, that will power both sides of our distro panel with maybe about 15A per side. Probably wouldn't run much, but might run an AC on each side, assuming I could get past start-up loads. I've never tested.

Actually, we do have another adapter, a simple 15-to-30 plug. We've only used that once or twice to charge batteries for a while while on the hard in winter... and that's probably the only time we've used the 30-to-50 as well. A daisy chain from a 110V outlet out in the back parking lot...

-Chris

twistedtree · Sep 5, 2015

Our boat is also 50A 120/240V.

We carry a 30A to 50A reverse Y adapter. One trick with these is to also carry one and preferably two 30A cords. We have found lots of situations where the two 30A outlets needed to create 240V are not right next to each other, and the 30A cords lets you reach then as needed. We carry two 25' 30A cords for this.

We also carry a 50A 120/240V splitter. This allows us to share a 50A outlet with another boat, if needed. Obviously the combined power draw of the two boats is limited to 50A, but when push comes to shove, you do what you need to do.

When we start cruising in areas with non north american power, we will add a variety of 16A and 32A 230V adapters to the mix, but that's a project for another day.

ksanders · Sep 5, 2015

We can do 120V 30 amp or 120/240 volt 50 amp.

There is no such thing as 125 volt or 250 volt power in the United states. There is also no 110 volt either.

Other than those we use our generator.

Actually we prefer our generator to shore power.

O C Diver · Sep 5, 2015

ksanders said:
We can do 120V 30 amp or 120/240 volt 50 amp.

There is no such thing as 125 volt or 250 volt power in the United states. There is also no 110 volt either.

Other than those we use our generator.

Actually we prefer our generator to shore power.

I'm aware of USA voltages. The 125 and 250 volt are the rating /voltage identifications on the plugs and receptacles if you hadn't noticed.

Ted

ksanders · Sep 5, 2015

O C Diver said:
I'm aware of USA voltages. The 125 and 250 volt are the rating /voltage identifications on the plugs and receptacles if you hadn't noticed.

Ted

Of course I noticed Ted.

The plugs are rated up to those listed voltages, just like why most devices I work with daily are listed as up to 600 volts even though in the USA 600 volts does not exist (although it does exist in Canada).

You might have thought (from the tone of your post) that it is common knowledge, but I assure you that VERY few members of the boating community know that 125 volts and 250 volts, and even 110 volts does not exist.

And I thought someone might find that tidbit interesting.

O C Diver · Sep 5, 2015

Sorry, thought that was directed at me.

Ted

ksanders · Sep 5, 2015

O C Diver said:
Sorry, thought that was directed at me.

Ted

No harm, I didn't think you were upset.

Somewhere deep in my memory I have a thought that you might be an electrical or electronics professional of some sort, so of course it was directed at the masses.

What is fun is when you explain the hows and the whys of something as seemingly simple as AC power, and see the light come on in their head when the get it.

As you know it all relates back to 120 volts. Everything else is a mathematical function of that.

twistedtree · Sep 6, 2015

ksanders said:
What is fun is when you explain the hows and the whys of something as seemingly simple as AC power, and see the light come on in their head when the get it.

As you know it all relates back to 120 volts. Everything else is a mathematical function of that.

Please explain. Sounds like there might be some history that I don't know?

ksanders · Sep 6, 2015

twistedtree said:
Please explain. Sounds like there might be some history that I don't know?

It's the math behind it that makes up the hows and whys. really simple stuff actually, but interesting.

If we start with the standard of 120 volts and work backwards, and taking into account that transformers work in ratios then...

120* 60 = 7200 volts phase to neutral, thats a very common voltage for the lines that you see everywhere. Take three of those lines, one per phase and the voltage phase to phase is the square root of three or 1.73, making 12,470 volts phase to phase.

Now working backwards if you want to feed a house with "single phase" power or 120/240 volts then you would take a 30:1 transformer, connect it to one of the phases (hence the term "single phase"), center tap the low voltage side of the transformer and ground that you will get two 120 volt lines phase to ground or phase to neutral and 180 degrees opposite in phase from each other, and one 240 volt line if you measure phase to phase.

Now take three 30:1 transformers, each connected to their own phase. Conect the other high voltage wires together, and ground it. What you will get is what is commonly refered to as 120/208 volt three phase power. That is three 120 volt phases, each 120 degrees out of phase with each other, and if you measure phase to phase you will read 120 volts* the square root of three or 208 volts phase to phase.

Thats all for right now, I'm at work this week and have a 06:30 AM meeting I have to attend.

smitty477 · Sep 6, 2015

Hello OC Diver,

"While 30 amp 125 volt receptacle would be the logical choice, 50 amp receptacles seem substantially more robust. Wondering if cruisers with 50 amp service carry adapters to 30 amp receptacles and the vise versa?"

We have had the same choices to make in past boats when we cruised various areas clos by but greatly different in their power support. We ended up using a combination approach which allowed us easy access to power regardless of their 30/125 or 50/125 or 50/250 amp power poles. I have cut and pasted an older post we made on the BOC on this same subject below as it might give you some ideas on what will or will not work in your application.

Bayliner 4788 dockside power option - There are many options availablewhen deciding to add to your dockside power options but much of these choicescan be dictated by where you will be using your boat. Although there has been amove to have upgraded dockside power available in recent years we stillfrequent marina’s, museums, and small docks which have limited power optionsand reward those with flexibility in connecting. Some of these destinationslike Mystic Seaport as well as a few up the Hudson River will have longerdockside runs even if available as does Block Island on a busy weekend. So yourultimate decision to fit out your boat for dockside power should only be madeafter a careful look at how you may need you utilize it over future years.
Boat side

The 47XX with the A/C option‘normally’ has 3 incoming lines labeled 1, 2 and 3 from the bow to stern on the starboard side.Lines 1 and 2 are utilized for all circuits other then A/C and heat and line 3normally has 3 A/C units and 4 heaters on it as well as spares. Lines 1, 2& 3 can be paralleled on the breaker panel with 2 switches which are: line#2 paralleled (P) on line #1 and line 3 P on line #1. By throwing one or bothswitches you can direct power that is brought to the boat on line #1 to eitheror both of lines 2 & 3. Please note that the max power available for alllines will be that which is brought to line #1. If you follow the graphic lineson the inside breaker panel you will get a feel for which line feeds which circuitsand you can monitor your total amp load with the meters at the tops of thebreaker strings.

Inlet configurations

‘Normally’ you will get30amp/125 volt inlets on lines 1 & 2 and a 50amp/125 inlet on line 3 withthe A/C and genset option. Many of these have been rewired at the dealer and/orwith previous owners so checking exactly what you may have at the inlet andbehind the panel (wire gage and switch config.) is a mandatory 1ststep. You will likely find that all wires from the inlets to the switches andbreaker panel bus lines are 8 gage or better but there have been some observedto be 10 - gage (30 amp max) in some re-wires.

Options

It is not too difficult tochange a boats inlet as long as you are capable of ensuring that the wiring andbreakers behind it can support the new amperage. It is also fairly easy to buymany premade dockside lines and adapters as long as the expense is considered.You can reasonably estimate your power needs by watching and recording youractual amperage usage at 125 volts with the meters at the tops of the 3 breakerlines while you use your boat. Turn on all electrical appliances that you wishto connect and add up the 3 lines for a total (note - when paralleled meter 1will read a sum of what is paralleled at that time). What is more difficult tofigure is the dockside power that will be available for you to hook up to whenyou are visiting specific destinations.

Our solution (certainlynot the only one)

We have chosen to go with a veryflexible solution since we see many varying dockside power where we cruise eachyear. Our goal was to have the ability to hook up to whatever power wasavailable and have the potential dock line runs be very long for crowded orlimited marina’s. Our boat came with the ‘normal’ 30/125 inlets on line 1 &2 and a 50/125 on line #3. It also came with 2-30 amp 50' dockcords as well as2-50amp/125 by 50' dockcords and an adapter or two. We changed the inlet online #1 to a 50/125 and made sure that the supporting hardware was up to the task(it was). We then made a 65' long 50 amp/250 volt dockside line from underwaterrated mining cable with the associated ends to feed a 50/250 (dockside) to50/125 (boatside) “Y” adapter that we purchased. We also have 2 single adaptersthat are 30amp dock to 50/125 boatside as well as an adapter that is 15 ampdock to 30 amp boatside.

Some common marina hook-ups for us (there are many more)

Preferred is a 50/250 docksidetower that we hook our 50/250 cable to and run to the boat through our 5/250“Y” to lines 1 & 3. We parallel line 1 & 2 and this gives us 50/125 onlines 1 & 2 and 50/125 on line 3 which pretty much can power everything atonce ( well not quite - but close).

Next is a 30 amp tower that alsohas 50/125 available - we run one 30 to line 1 & 2 “P” with the singleadaptor and the 50 to line 3 with the 50/125 cord. We now have 80 amps at125available and can add the other dockcord lengths to the run if necessary.

Another is a 2-30 amp docksidetower - we run 2-30 amp dockcords through the 2 single 30 amp to 50/125adapters to lines 1 & 3 (1 & 2 are “P”). This gives us a total of 60amps/125 at the boat.

So there are many possibilitieson how this can be configured based upon your cruising needs.

Hope this helps. Ron &Karen “No Worries”

N4712 · Sep 6, 2015

ksanders said:
It's the math behind it that makes up the hows and whys. really simple stuff actually, but interesting.

If we start with the standard of 120 volts and work backwards, and taking into account that transformers work in ratios then...

120* 60 = 7200 volts phase to neutral, thats a very common voltage for the lines that you see everywhere. Take three of those lines, one per phase and the voltage phase to phase is the square root of three or 1.73, making 12,470 volts phase to phase.

Now working backwards if you want to feed a house with "single phase" power or 120/240 volts then you would take a 30:1 transformer, connect it to one of the phases (hence the term "single phase"), center tap the low voltage side of the transformer and ground that you will get two 120 volt lines phase to ground or phase to neutral and 180 degrees opposite in phase from each other, and one 240 volt line if you measure phase to phase.

Now take three 30:1 transformers, each connected to their own phase. Conect the other high voltage wires together, and ground it. What you will get is what is commonly refered to as 120/208 volt three phase power. That is three 120 volt phases, each 120 degrees out of phase with each other, and if you measure phase to phase you will read 120 volts* the square root of three or 208 volts phase to phase.

Thats all for right now, I'm at work this week and have a 06:30 AM meeting I have to attend.

Kevin, thanks for explaining that, always fun to learn new stuff.

smitty477 · Sep 6, 2015

O C Diver,

"Have 3 friends with boats but no gensets that I will do some short cruises with. Have run a dedicated 110 volt 25 amp circuit to the veranda that I plan to put a shore power receptacle on for their use when we raft up. You can tap into my genset, but go sleep on your own boat."

FIW - this can be both a sigificant problem and potentially very unsafe if the ground is dropped or weak for any reason whatsoever. A suggestion would be to mention this to a marine electrician you respect so he can explain to you the possibilities for your consideration.

FF · Sep 7, 2015

"Have 3 friends with boats but no gensets that I will do some short cruises with. Have run a dedicated 110 volt 25 amp circuit to the veranda that I plan to put a shore power receptacle on for their use when we raft up. You can tap into my genset, but go sleep on your own boat."

These are called Buddy Plugs , even tho you are providing a socket for their use.

O C Diver · Sep 7, 2015

smitty477 said:
O C Diver,

"Have 3 friends with boats but no gensets that I will do some short cruises with. Have run a dedicated 110 volt 25 amp circuit to the veranda that I plan to put a shore power receptacle on for their use when we raft up. You can tap into my genset, but go sleep on your own boat."

FIW - this can be both a sigificant problem and potentially very unsafe if the ground is dropped or weak for any reason whatsoever. A suggestion would be to mention this to a marine electrician you respect so he can explain to you the possibilities for your consideration.

Yes, I understand the grounding requirements and will have my buddies test for ground continuity whenever they connect to my power.

Ted

JDCAVE · Sep 7, 2015

Bay Pelican said:
In the United States in Canada you will rarely see the 20 amp twist lock

The service at my marina is 20 amp twist lock and we've come across it at other locations in BC. I had a home made adapter from the PO, but it fried last winter. I bit the bullet and bought a Marinco adapter for $125 Cdn!!! The marina says they are switching everything over to 30 amp. I'll believe it when I see it!

Jim
Sent from my iPad using Trawler Forum

Shore power adapters

O C Diver

Guru

Bay Pelican

Moderator Emeritus

ranger58sb

Guru

twistedtree

Guru

ksanders

Moderator Emeritus

O C Diver

Guru

ksanders

Moderator Emeritus

O C Diver

Guru

ksanders

Moderator Emeritus

twistedtree

Guru

ksanders

Moderator Emeritus

smitty477

Guru

N4712

Guru

smitty477

Guru

FF

Guru

O C Diver

Guru

JDCAVE

Guru

Similar threads

Latest posts