30 amp source with 50 amp system

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Tony B said:
So, this smart part with the solid state circuitry is inside the cord itself?
I can run my boat entirely off one 30A cord ( as long as I don't go over 30A) or two 30A cords to a 50A "Y".
My boat has worked with and without the smart cords.
How did my model year 1986 work without the smart cords?
Click to expand...


There are two different kinds of 30-to-50 or 50-to-30 Y cords.

One (The "Smart" or "Reverse" Y) takes two 30A supplies from shore, and converts those into single 50A supply. Given certain conditions (30A circuits are in opposite phase, ours says it needs a minimum of 208V to work; see the 167RYN in the Marinco link, and note the big honkin' box at the junction).

The other is an adapter that starts with a single 50A shore source, and splits that into two independent 30A supplies. (See MARINCO EEL Y Adapter, 30A F-50A/250 M, Power Cord Adapter at West Marine)

For your description, sounds like you've encountered the latter? I guess this because you can run your boat on two separate 30A cords, assuming your shore supply is two 30A circuits. (Yes?) I too could run select stuff on both 30A circuits on a previous boat using only one 30A shorepower cord... as long as I didn't exceed 30A.)

If the latter is correct in your case, you would have no use for the Smart/Reverse Y version, because you don't need a 50A supply to run stuff in the boat. (And that can be a good thing; they're expensive.)

-Chris
 
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Wxx3 said:
I may be making an assumption, bit let's take the question as asked.
If no 50 A outlet, he plugs his 30 A cord into the outlet without using the adapter. Wasn't that the question?

Then, on the boat, on one of his circuit panels, the circuits shold be separated (MY ASSUMPTION), if so, he diecides what circuit to power (based on what he wants to use) IF NOT, THEN READ ALL THE ABOVE BC IDHAFC.:nonono:
Click to expand...

:)

Not exactly. Johnny started with:

I am chartering a boat with a 50 amp electrical system. It has a "Y" adapter with the power cord so when visiting a marina with only 30 amp service you can connect to two 30 amp receptacles.

That would mean the Y adapter is a twin-30-to-50A Smart (or Reverse) Y... which creates 50A out of twin 30s. (IOW, not a simple 50-to-twin-30A adapter, for a twin 30A boat.) And the boatside connector is a 50A male connector, needing a 50A female led from shore.

And then:

My question is, if there is only one 30 amp receptacle available can I connect one leg of the "Y" adapter to the 30 amp receptacle...

And the answer to that is no.

(Unless there's an exception because it's a 50A/125V (not 240V) boat; see the 166AY product in the earlier Marinco link. But that wouldn't jive with the original statement about making 50A out of "two 30 amp receptacles.")

OTOH, without using that particular Smart/Reverse Y adapter -- your point, I think? -- there may be a way to power some of the boat (depends on the boat's AC distro panel, etc.), using a single 30-to-50A adapter. We can do that, to a certain extent... but I haven't experimented much with that, haven't needed to.

-Chris
 
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A smart reverse if used correctly can bring in 60 amps to the boat...though it does depend on the interior panel set up.

30 amps per leg and on the interior...each 50 amp sub panel/buss will only receive 30 amps but there are 2 most often so the total amperage the boat can siphon is 60 instead of it's normal 100.
 
ranger42c said:
There are two different kinds of 30-to-50 or 50-to-30 Y cords. ...............

The other is an adapter that starts with a single 50A shore source, and splits that into two independent 30A supplies.
YES

I guess this because you can run your boat on two separate 30A cords, assuming your shore supply is two 30A circuits. (Yes?)

I too could run select stuff on both 30A circuits on a previous boat using only one 30A shorepower cord... as long as I didn't exceed 30A.)
YES

If the latter is correct in your case, you would have no use for the Smart/Reverse Y version, because you don't need a 50A supply to run stuff in the boat. (And that can be a good thing; they're expensive.)
The advantage would be the 50A capacity
-Chris
Click to expand...

Thanks for the simple explanation.
Tony B
 
Johnny said:
Thanks for all the info though!..... I think I may be a able to use a 30 to 50 amp adapter but will only power some of the equipment. ....
Click to expand...

I don't think you will be able to do this, at least not with any commercially available adapter. The adapters that are commercially available are:

- 50A 120/240V shore power to 30A 120V boat. This is going in the wrong direction from what you need.

- 30A 120V shore power to 50A 120V boat. This is going in the right direction, but your boat has a 50A 120/240V inlet, not a 120V inlet. They are different and one will not plug into the other.

My boat is set up the same as the one you are chartering with 50A 120/240V on the boat side. I have a Smart Reverse Y that plugs into two 30A 120V shore outlets and combines them to fit a 50A 120/240V boat-side plug. You only get 30A @ 20/240V, but it works.

In the marinas I've visited that only had 30A service, I was always able to find two outlets. The one problem i DID encounter was 30A outlets that were spaced pretty far apart. It's very possible, perhaps even probably that the two 30A outlets you need to plug into are NOT on the same power post. In that case, you need a 30A extension cord or two to reach both outlets. In Eastern Canada, 50A service is rare outside of the big cities. Everywhere else it's just 30A. It wasn't long before I went and bought an extra 30A cord so I could always reach two 30A outlets.
 
Thanks Twisted. This is exactly what I needed. And thanks to everyone for your thoughtful responses.
 
Johnny

You are right to ask. All of us started with less knowledge than we have now.

In summary a cruising boat with 50 amp service usually has both a smart Y which it can use with two 30 amp outlets and a 30 to 50 amp adapter to use when there is only one 30 amp outlet. Most cruising boats in this situation also carry a 30 amp 50 foot cord so that they can connect one half of the smart Y to the post at their slip and the other half of the smart Y using the 50 foot cord to a post at another slip.

Since smart Ys require that the two 30 amp plugs are out of phase to operate you may find that even when you connect to two different outlets the smart Y will not allow the current to flow through. In such case try a different outlet or switch to the 30 amp to 50 amp adapter.
 
Bay Pelican said:
In summary a cruising boat with 50 amp service usually has both .... and a 30 to 50 amp adapter to use when there is only one 30 amp outlet. ....
Click to expand...

Just note that I don't believe there are any commercially available 30A to 50A 120/240V adapters. All the commercially available adapters are 30A to 50A 120V, not 120/240V. The 50A plug/socket is different and one will not attach to the other.

By the way, another way to got a single 30A outlet to power (at reduced loads) a 50A 120/240V boat is via an isolation transformer with appropriate taps. The 30A 120V goes on one side of the xformer, and you pull the 120/240V off the other side with the neutral as a center tap on the transformer. If you have a boat with an isolation transformer and 50A 120/240V service, it's often a trivial wiring exercise to wire in an alternate 30A 120V inlet. Many Nordhavns are built this way so you can plug right into a 30A dock post and have fully functional 120/240V service on board, but of course at reduced load. But it's enough to run your 240V oven, or dryer, or water maker one at a time.
 
ranger42c said:
:)

Not exactly. Johnny started with:

I am chartering a boat with a 50 amp electrical system. It has a "Y" adapter with the power cord so when visiting a marina with only 30 amp service you can connect to two 30 amp receptacles.

That would mean the Y adapter is a twin-30-to-50A Smart (or Reverse) Y... which creates 50A out of twin 30s. (IOW, not a simple 50-to-twin-30A adapter, for a twin 30A boat.) And the boatside connector is a 50A male connector, needing a 50A female led from shore.

And then:

My question is, if there is only one 30 amp receptacle available can I connect one leg of the "Y" adapter to the 30 amp receptacle...

And the answer to that is no.

(Unless there's an exception because it's a 50A/125V (not 240V) boat; see the 166AY product in the earlier Marinco link. But that wouldn't jive with the original statement about making 50A out of "two 30 amp receptacles.")

OTOH, without using that particular Smart/Reverse Y adapter -- your point, I think? -- there may be a way to power some of the boat (depends on the boat's AC distro panel, etc.), using a single 30-to-50A adapter. We can do that, to a certain extent... but I haven't experimented much with that, haven't needed to.

-Chris
Click to expand...

:facepalm:

yes, that was what I was trying to say. Thanks Ranger for being more articulate.
 
Well I am almost afraid to ask, but can you please explain what "out of phase" means? I have seen it referenced several times.
 
Johnny said:
I am chartering a boat with a 50 amp electrical system. It has a "Y" adapter with the power cord so when visiting a marina with only 30 amp service you can connect to two 30 amp receptacles. My question is, if there is only one 30 amp receptacle available can I connect one leg of the "Y" adapter to the 30 amp receptacle and be careful how much equipment I run? Do you think I could run reverse cycle heat and a few cabin lights? Is it dangerous to leave one leg of the "Y" adapter open?

Thanks
Click to expand...
I'm not sure it's possible to answer the question without more information. At the boatside male plug where you attach the cord, what is stamped on the cover - 50 amp 250v or 50 amp 120v? I assume the latter. I also assume the "Y" is comprised of two 30 amp 120v male plugs and one female 50 amp 120 volt plug, and if so, the answer is no, you can't safely connect just one leg of that Y if the Y is not 'smart' because the male plug that is not plugged in will still be live and a shock hazard. If it is smart, then it won't operate at all with just one leg plugged in. If the Y has some other plug configuration, what is it?

Probably what you need is this: http://www.marinco.com/en/111a/pigt...le-connector-and-a-30a-125v-locking-male-plug

Here's an explanation of what phasing means in this context: http://wiki.answers.com/Q/What_is_the_meaning_of_out_of_phase
 
Johnny said:
Well I am almost afraid to ask, but can you please explain what "out of phase" means? I have seen it referenced several times.
Click to expand...


Let me give it a try in layman's terms (those who actually know what they are talking about can correct me).

Normal 110 volt North American wiring has a positive (hot) and a neutral wire. The positive sends the juice out and the neutral returns the juice to the source/ground. However alternating current means that the a positive juice is sent out alternating with a negative juice (60 times a second).

North American 220 volt substitutes a second 110 volt hot wire for the neutral. Both hot wires send out alternating current but there is no neutral. For the system to work the positive and negative juice cannot be timed the same for both hot wires. If they are off sync so that when hot one is sending out positive and hot two is sending out negative then each hot wire's "neutral" is the other hot wire and the system works. This being out of sync is called being out of phase.
 
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>North American 220 volt substitutes a second 110 volt hot wire for the neutral. Both hot wires send out alternating current but there is no neutral.<

Yes,,, BUT there are few US boats that have pure 240 devices on board .

So both the ground and neutral are REQUIRED for 120V operation from that 240V Source .

Power hose , noisemaker or inverter,
 
Delfin said:
........... I also assume the "Y" is comprised of two 30 amp 120v male plugs and one female 50 amp 120 volt plug, and if so, the answer is no, you can't safely connect just one leg of that Y if the Y is not 'smart' because the male plug that is not plugged in will still be live and a shock hazard. ..........
Click to expand...

If it's not illegal to sell such an adapter, it should be because as you mention, the exposed male prongs of the unused leg would be electrically hot. I wouldn't call this a "shock hazard", I would call it an "electrocution hazard". Picture a child walking down the dock grabbing the plug to see what it is.

This is also the warning to all the cheapskates who decide that they can go to the home center, buy two plugs, a socket and a couple feet of wire and make their own "Y" adapter.
 
Bay Pelican said:
Let me give it a try in layman's terms (those who actually know what they are talking about can correct me).

Normal 110 volt North American wiring has a positive (hot) and a neutral wire. The positive sends the juice out and the neutral returns the juice to the source/ground. However alternating current means that the a positive juice is sent out alternating with a negative juice (60 times a second).

North American 220 volt substitutes a second 110 volt hot wire for the neutral. Both hot wires send out alternating current but there is no neutral. For the system to work the positive and negative juice cannot be timed the same for both hot wires. If they are off sync so that when hot one is sending out positive and hot two is sending out negative then each hot wire's "neutral" is the other hot wire and the system works. This being out of sync is called being out of phase.
Click to expand...

To simplify things, let's color code the wires in the typical manner and the typical service:

Alternating Current electrical service (in the USA) consists of three current carrying conductors, typically a black "hot" conductor, a red "hot" conductor and a white "neutral" conductor. The black and red conductors are out of phase with each other and there is a potential of 220 volts (nominal) between them. The white conductor is the neutral and there is a 120 volt (nominal) potential between it and either the black or red conductor.

120 volt appliances like TV sets, toasters, microwaves, hair driers, etc. can be connected either between the black conductor and the white neutral conductor or between the red conductor and the white neutral conductor. Either connection delivers 120 volts.

Appliances like most electric ranges, most electric driers, and larger electric water heaters or airconditioners are connected between the red and black conductors and receive 220 volts. Often they will also have a connection to the neutral conductor to supply 120 volts to lights, clocks, controls, etc.

I've left the grround out of this description just for clarity. There should be no current flow in the grounding conductor except in the case of a fault.
 
Not positive...but this one makes it sound like the cord isolates and allows the use of one leg only...

Y & Reverse Y Adapters

  • The reverse "Y" adapter has two male plugs with special power isolation circuitry for added safety.
  • When on plug is connected to a receptacle, the circuitry isolates the second plug.
  • The reverse "Y" provides 50A 125/250V power when only 30A 125V receptacles are available.
  • Boat side: 50A 125/250V w/ sealing collar system.
  • Dock side: (2) 30A 125V locking.
 
>I wonder which leg it powers on the 50A side, or if they short them both together.<

For our bus conversion we have NO 240V users , so a special power cord that does JOIN together the red & black onboard is used for either 120v 30A or 120V 15A power supply.

Works fine , BUT the on board power use does need to be watched .

The Desperation Y for folks that have massive dockside power requirements needs to be complex to assure two different legs , one red and one black , from the same feed lines are used.
 
twistedtree said:
Huh, very interesting. I wonder which leg it powers on the 50A side, or if they short them both together. Too bad Marinco's literature doesn't give a wiring diagram or otherwise say what it does.
Click to expand...


Don't know, but suspect that depends on the boat's distribution system, not necessarily the cord.

I know on our boat that this set-up will power our "port side" stuff, which includes the battery charger among other things. I was only interested in a quick winter time top-off charge at the time, and the boat was on the hard anyway, so I didn't investigate further.

-Chris
 
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I looked on the Marinco website...often the plugs are labeled so you could see what goes where...but on that particular cord the labels were partially left off or obscured.

On 50A panels that don't have 220 setups, there's usually a combiner breaker/switch.

Not sure how it would work (or not) with boats that have a 220V
 
psneeld said:
I looked on the Marinco website...often the plugs are labeled so you could see what goes where...but on that particular cord the labels were partially left off or obscured.

On 50A panels that don't have 220 setups, there's usually a combiner breaker/switch.

Not sure how it would work (or not) with boats that have a 220V
Click to expand...
I have a 50 amp male pig tail that will just give you 30 amps and 50 amp female that will plug intp a 50 amp cord and olnly give you 30 amps,they only use one leg and I also have a 50 amp hubell splitter that splits to 50 amps 110 all are for sale
 
capt jerry said:
I have a 50 amp male pig tail that will just give you 30 amps and 50 amp female that will plug intp a 50 amp cord and olnly give you 30 amps,they only use one leg and I also have a 50 amp hubell splitter that splits to 50 amps 110 all are for sale
Click to expand...

the question is...what type of panel inside the boat? 220V at all? 2 busses?
 
psneeld said:
the question is...what type of panel inside the boat? 220V at all? 2 busses?
Click to expand...
my boat was only 30 amp, but they were nice when I got to a place where all the 30s were being used and I could plug in to a fifty and come out with 30, on the splitter it was 50 amp 220 but split down to 50 amp 110 which years ago they had on the old hatteras,but they have a adapter that you can plug into the 50amp 110 and come out with 30 110
 
capt jerry said:
my boat was only 30 amp, but they were nice when I got to a place where all the 30s were being used and I could plug in to a fifty and come out with 30, on the splitter it was 50 amp 220 but split down to 50 amp 110 which years ago they had on the old hatteras,but they have a adapter that you can plug into the 50amp 110 and come out with 30 110
Click to expand...

I'm guessing the 50 amp 220 was actually just a 50 amp with 2 110 legs that could give 220 if wired a certain way...like most are today...
That's why you are able to do what you are doing...
 
I have several different adapters on my boat, both commercially made and home made. My boat is wired for two 30A Lines.
Last fall while in a boat yard on the hard in Texas City, Tx they had these 4 prong 220V outlets. I had never seen them before and my neighbor told me that the welders use those sockets. He just happened to have a home made adapter to convert the 4 prong 50A 220V socket to a 30A 110V socket. Being a little weary, I run my multi-meter across it and it checked out just fine so I used it and all was good.
Last week I ran into a guy who just bought a 48' something or other when he pulled into Gulfport Harbor in Ms. It was going to be a cold night and most of his electric had been fried. He was trying to borrow a heater and I had already loaned out my spare gas one. Fortunately, one of the harbor security women had a spare one in her boat and loaned it to him. The admiral had just made some chili and so I carried some over there. He told me he just bought the boat in New Orleans and went to a private dock near there to spend the night and when he plugged in, the fireworks began.
Moral of the story - always have a multi-meter when in doubt.
 
just bought the boat in New Orleans and went to a private dock near there to spend the night and when he plugged in, the fireworks began.
Moral of the story - always have a multi-meter when in doubt.

AND the FIRST thing to check is the power being offered at the pole,, as it may be to no standard but that dock !!!

Trust but verify , works every time.
 
Tony B said:
... went to a private dock near there to spend the night and when he plugged in, the fireworks began.
Moral of the story - always have a multi-meter when in doubt.
Click to expand...

Good luck with that.

Few consumer multimeters have probes that will fit into a dock pedestal socket deeply enough to reach the contacts.

This one sounds more like a boatside or cord issue than the socket.
 
Johnny said:
Well I am almost afraid to ask, but can you please explain what "out of phase" means? I have seen it referenced several times.
Click to expand...

Three wires; black, red, white. Alternating current.

The black and the red are each 120 volts with respect to the white (neutral). The black one is positive at the same time the red is negative and vice versa. Out of phase. That makes 220 volts between them.

If the black and red were both 120 volts with respect to the white neutral wire at the same time, they would be in phase and there would be no voltage difference between them.
 
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