208volt Problem at Marinas

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When it comes to AC, everything I see are reverse cycle heat pumps and they are all 120v.

I'm guessing down south reverse cycle heat pumps are not adequate for AC. Still I would expect the AC units to use two 120v hot legs still by passing the need for a single 208v hot wire, or is there something I am missing here.
 
diver dave said:
The marina is buying 3 phase and is billed accordingly. I'm supposing these dockside transformers are not utility owned, but marina owned. Therefore the marina is determining what voltage they shall give you, not the utility.

Gary, is this correct on the ownership?
Click to expand...

Correct, the utility owns the main input transformer and each dockside transformer is marina owned.
 
tiltrider1 said:
When it comes to AC, everything I see are reverse cycle heat pumps and they are all 120v.

I'm guessing down south reverse cycle heat pumps are not adequate for AC. Still I would expect the AC units to use two 120v hot legs still by passing the need for a single 208v hot wire, or is there something I am missing here.
Click to expand...


No, two 120 volt hot wires from a 208 wye transformer will give you 208 volts because they are only 120 degrees out of phase if you have 230 volt compressors. If you have 2 120 volt units each one will get 120 volts because they are reacting with the neutral, not another leg even though they may be drawing from two different hot wires. A balanced load.
 
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A search on line of what marinas have is pretty much futile. I did see this one from Miami beach Marina, space for 400 boats, the largest to 250 ft.

"30amp/50amp/100amp single phase/100amp three phase, 480 volt"
 
So I have ran into problems with 208. I have two different marinas that have 208 that I have gone to. A marina in Pensacola where I have no problems. However, at St. Pete Municipal they have 208 and if there is more than 2 boats on the transient T dock I have sufficient voltage drop that I can only run one of our AC units. Maybe two if they are small. We have five units and usually run three at a time. They tried to put us closer to the transformer but would have needed to move a bunch of boats. Ran the generator and they gave us a partial refund.
 
If you are measuring the power to your boat and it is lower than 120, it is probably because you are overloading your service. Unplug everything and measure the input voltage, then start plugging everything back in. As soon as you measure a voltage drop, I believe its 10%, you are done. More load than that and you are risking a failure and a fire. Try feeling how hot your shore power plug is too, if you feel any heat and there is no way to measure voltage, you are risking a failure and fire so unplug some devices. This is especially true in the winter heating time when your boat will not be used for long times.

Hot water tank?
Space heater?
Vent fan?
Battery charger?
Cell phone charger?
Lights?
Fridge?
Water pump?
Ais?
 
I was trying to understad why I have never run into this 208v issue in B.C. Canada. Then it dawned on me. We can never find more than 50a 125v outlets. That’s why we use step up transformers, so even if we found a 50a 125/250v outlet we are seeing 120v on both panels and 240v from the step up transformer.
 
Rogerh said:
So I have ran into problems with 208. I have two different marinas that have 208 that I have gone to. A marina in Pensacola where I have no problems. However, at St. Pete Municipal they have 208 and if there is more than 2 boats on the transient T dock I have sufficient voltage drop that I can only run one of our AC units. Maybe two if they are small. We have five units and usually run three at a time. They tried to put us closer to the transformer but would have needed to move a bunch of boats. Ran the generator and they gave us a partial refund.
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Undersized wiring, corroded connections or a Marina adding a "few" more towers to a chain without upgrading the feeds can all contribute to line loss. It happens all the time.
 
That's what the dock master said, that they added to many feeds. Almost all my big systems, AC, pumps, and so on are 220, not 120. This according to the dock master is a problem at the T head. I have no problem at other marinas. I could watch my 208 which read about 205 go down to 202 when other boat AC kicked on. That was before I put any of my loads on. Frustrating but they did make good and gave me a reasonable refund.
 
diver dave said:
hmmm, not true for the 1 billion homes on the planet? But true for a few thousand marinas with a similar demand for service?

In all my travels, I have come across 1 house with 3 ph service. We have entire multi-square mile neighborhoods supplied with single phase. Efficiency is high on the list for utility distribution. Few residential areas have even 3 phase available.

so, my fundamental question remains. Who on a dock wants 3 phase??
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For single family homes, there is a transformer on a pole, and it serves a few homes. Then there is another transformer on another pole and connected to a different phase of the 3-phases on the poles, and it serves a few other homes. The key is that they are spaced out.

If you look at the wiring in an apartment building or other high-density facility, I think you will find the same 208/120V setup that you have in a marina.

So I maintain that it's about economics and how you best provide power to a high density collection of consumers.

Here's an example. Say you want to deliver power to 12 50A dock pedestals. With 3 phase you need 4 conductors capable of carrying 200A each, and a single 200A 3-phase transformer. Four 50A outlets can be placed on each of three line to line combinations, and each with a neutral connection to support 120V.

With single split phase, you need 9 conductors capable of carrying 200A each, and three 200A single phase transformers. Four 50A outlets can be placed on each of the 200A, 3 wire circuits.
 
diver dave said:
In all my travels, I have come across 1 house with 3 ph service. We have entire multi-square mile neighborhoods supplied with single phase. Efficiency is high on the list for utility distribution. Few residential areas have even 3 phase available.
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For what it's worth, the power on the street poles is always 3-phase. Up high, you will see either 3 or 4 conductors. That's 3 phase, with or without a ground (usually without). As you get more off the beaten path, those three wires may drop down to two or one. But they are still the legs of a 3 phase system. They have just run one leg down one street and another leg down another street.

It's definitely true that all three of the phases are very seldom brought into the house. I have seen one or two, but it's very rare. And unless you are on a street where the power co only run one or two legs of the 3 phase down that street, you can get 3 phase power in your house if you want it.
 
I have zero doubt this 208 fiasco is caused by economics. Since there is no "rule" or "code" violation, it's free market, buyer beware.
Most of the above points are arguable. I'm not seeing how secondary wiring becomes cheaper depending on the transformer, it doesn't. No matter the source, each post needs a 3 wire (L1,L2,N) for service. Each rated at 50A. It could be a more compelling argument that you need LESS copper at 240 than at 208V, since the current will be less. You are NOT feeding 3 phase to the user, so you don't get any proposed advantage. It's only the primary side we are discussing.

The sum story is that the marinas have a way to make things cheaper, at the cost to the boater. Boaters want 240V, they get 208. It's that simple. Worse yet, many marinas don't seem to be able to describe what voltage they actually supply. They may even advertise 50A 240/120, but give 208/120. Sad.

The right way to do this is run phase A primary down one set of docks, to 240/120 split transformers, Phase B down set 2, phase C down set 3. etc. Mega yachts get 480 3 phase at the huge dock. Done.
More transformers, but each is smaller. And, you only have 1 HV conductor plus N down each dock. Not 3 plus 1.
 
Is there usually / always only one neutral on each side of a power pedestal?

My boat has 50 amp 125 / 250 volt service. Everything in the boat is 120 volt. Occasionally I end up at a slip that has no 50 amp receptacle on the power pedestal. Sometimes the two 30 amp receptacles yield 240 volts, sometimes 208 volts, and sometimes 120 as they are on the same phase. The smart box adapters from either Hubbell or Marinco have a problem with 208 and go into error mode (they're fine on 240 volts). They also error if the two receptacles are on the same phase.

Found an adapter that has two 30 amp males to a 50 amp 125 / 250 female without the smart box. It works very well. My only concern was whether both 30 amp receptacles in the power pedestal shared the same neutral and if they didn't, could that potentially be a problem?

Ted
 
diver dave said:
I have zero doubt this 208 fiasco is caused by economics. Since there is no "rule" or "code" violation, it's free market, buyer beware.
Most of the above points are arguable. I'm not seeing how secondary wiring becomes cheaper depending on the transformer, it doesn't. No matter the source, each post needs a 3 wire (L1,L2,N) for service. Each rated at 50A. It could be a more compelling argument that you need LESS copper at 240 than at 208V, since the current will be less. You are NOT feeding 3 phase to the user, so you don't get any proposed advantage. It's only the primary side we are discussing.

The sum story is that the marinas have a way to make things cheaper, at the cost to the boater. Boaters want 240V, they get 208. It's that simple. Worse yet, many marinas don't seem to be able to describe what voltage they actually supply. They may even advertise 50A 240/120, but give 208/120. Sad.

The right way to do this is run phase A primary down one set of docks, to 240/120 split transformers, Phase B down set 2, phase C down set 3. etc. Mega yachts get 480 3 phase at the huge dock. Done.
More transformers, but each is smaller. And, you only have 1 HV conductor plus N down each dock. Not 3 plus 1.
Click to expand...

I haven't opened up the wiring boxes on a dock to know for sure, but my assumption, using my previous example to illustrate, is that a single bundle of 4 conductors would run down the dock, and each 50A post would be tied into it. So yes, there are still 3 50A conductors to each post, but they are short - on the order of maybe 5 feet. The long run down the dock is the 200A 3-phase bundle of 4.

I think you are assuming that each dock post would be home run wired back to the transformer, and I don't think that is the case. Perhaps The Other Gary knows since this is his business.

You seem to feel cheated by 208 power, yet it is commonplace and has been for 100 years or more. You would be hard presses to find any commercial building or apartment building that isn't set up just like your marina.

I think the real issues here is that in some marinas, out at the end of the power runs, when it's hot and everyone has their HVAC on, there is too much voltage drop. 208V becomes 190V, and you effectively have a brownout, just like in cities when it's unusually hot out and power demand is very high. I expect that dock power demand had gone up quite a bit over the past 30 years, i.e. since many dock power systems were designed and installed, so they are likely loaded more then ever expected. Heck, there are lots of places that only have 30A 120V power, and consider 50A to be mega yacht power.
 
Further:

Many yachts that spend time at marinas also spend time at the owners home. As we noted, no homes have 3 ph, therefore no homes have 208V. This notion that boat owners must now comply with this marina imposed new standard of 208 is ridiculous. And now, the yacht owner needs to buy only 208V equip for the boat, and "make" 208 at home?

Saying that, certain equipment can very easily accomodate both, some can with performance degredations, and some can't. Notably, large motors and large transformers are challenging to design with wide input voltage tolerances. If 208 V is your target nominal, it will arrive, with cable drops, less than that, down to 187 V (-10%) and still be in spec. And, this does not include ship's internal losses. So now, the motor has to accomodate 187 to 265 (240 + 10%). That is alot to ask of a induction motor. A/C units, icemakers, air compressors, etc.
 
twistedtree said:
You seem to feel cheated by 208 power, yet it is commonplace and has been for 100 years or more. You would be hard presses to find any commercial building or apartment building that isn't set up just like your marina.
Click to expand...

I work with 3 phase up to and including 500kV with my work. All the way to 500kV DC in last week's station.
Cheated is close to the right term, but more to the point, is that it appears yacht owners are being abused. The uber rich are running 480 3 phase and don't have this issue. The smaller guys that don't have appliances beyond 120V are unaffected. Its that middle ground of middle sized yachts and workboats, that do have critical systems on 240V that are taking this in the shorts.

And,this apartment thing... Apartment dwellers are handed appliances that are speced to 208V and life is good. They don't even know about the issue. Who in an apartment is buying/running 3hp air compressors?
Boaters are transient beasts, and need to know what is in that yellow cord. They are being surprised.
 
This is from one of our recent installations. It is a single phase 120y/240v installation.
 

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This is also from one of our recent installations. It is a 3 phase 277/480v distribution system to the dock mounted transformer/distribution modules then 120/240v to the pedestals.
 

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diver dave said:
Further:

Many yachts that spend time at marinas also spend time at the owners home. As we noted, no homes have 3 ph, therefore no homes have 208V. This notion that boat owners must now comply with this marina imposed new standard of 208 is ridiculous. And now, the yacht owner needs to buy only 208V equip for the boat, and "make" 208 at home?

Saying that, certain equipment can very easily accomodate both, some can with performance degredations, and some can't. Notably, large motors and large transformers are challenging to design with wide input voltage tolerances. If 208 V is your target nominal, it will arrive, with cable drops, less than that, down to 187 V (-10%) and still be in spec. And, this does not include ship's internal losses. So now, the motor has to accomodate 187 to 265 (240 + 10%). That is alot to ask of a induction motor. A/C units, icemakers, air compressors, etc.
Click to expand...

You call it a "marina imposed new standard of 208V", yet it has been around for ages. There is absolutely nothing new about it. You have just tripped over it for the first time. Nobody sneaked into the marina in the middle of the night and rewired it to cheat you out of power.

I think your assessment is correct that it's boats "in the middle" that are potentially impacted. 120V boats see no difference, and 3 ph boats see no difference.

But rather than blaming the marina for the power they have had for who knows how many decades, perhaps you should look at the inadequate design of your boat's electrical system, and ask the builder why they designed it to work with one half of the marinas out there, but not the other half. Lots of boats in the "middle" are designed to use 50A 208/120 and 50A 240/120 interchangeably. Some utilize only the individual 120V legs - no problem. Others ensure that 240V devices are specified for 208-240VAC - no problem. Others use isolation transformers with automatic or manual step up - no problem.

I'd suggest you either improve you boat's electrical system so it can work with a wider range of marina wiring, or restrict your cruising to marinas that have power that meets your boat's limitations. It's really no different than dealing with Marinas that only have 30A 120V power, or that only have 50A 120V power. Do you expect all of them to re-wire to meet your boat's 240/120V needs? And what about marinas that have 50hz power? Should they change?
 
twistedtree said:
You call it a "marina imposed new standard of 208V", yet it has been around for ages. There is absolutely nothing new about it. You have just tripped over it for the first time. Nobody sneaked into the marina in the middle of the night and rewired it to cheat you out of power.
OK, the problem has been around for years. Still needs fixing. And, longer we wait, even more marinas need fixing.

I think your assessment is correct that it's boats "in the middle" that are potentially impacted. 120V boats see no difference, and 3 ph boats see no difference.

But rather than blaming the marina for the power they have had for who knows how many decades, perhaps you should look at the inadequate design of your boat's electrical system, and ask the builder why they designed it to work with one half of the marinas out there, but not the other half. The marinas are choosing the voltages, therefore the marinas are responsible for the voltages; this is not a utility issue to solve, and boats should not be expected to have a variable input autotransformer at the readyLots of boats in the "middle" are designed to use 50A 208/120 and 50A 240/120 interchangeably. Some utilize only the individual 120V legs - no problem. Others ensure that 240V devices are specified for 208-240VAC - no problem. Others use isolation transformers with automatic or manual step up - no problem.

I'd suggest you either improve you boat's I don't currently have a boat with AC rqmts electrical system so it can work with a wider range of marina wiring, or restrict your cruising to marinas that have power that meets your boat's limitations. It's really no different than dealing with Marinas that only have 30A 120V power, or that only have 50A 120V power. Do you expect all of them to re-wire to meet your boat's 240/120V needs? And what about marinas that have 50hz power? Should they change?
Click to expand...
So, far, I'm in the North America bog; I have no idea what euro marinas do, but I'd be very surprised if continental euro and UK are other than 230V 50Hz uniformly. If I was a critical European, I'd think our marinas are run by idiots.
 
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Bob Cofer said:
This is also from one of our recent installations. It is a 3 phase 277/480v distribution system to the dock mounted transformer/distribution modules then 120/240v to the pedestals.
Click to expand...

Thanks for posting!

We need to take note of the marinas that use this type of design. Load Marinanow, and Dockwa with the results. ;)
 
So I'm on a metered pedestal but instead of having a small meter on the pedestal I have a house type meter on shore and I deal directly with the power company for billing. Does that mean that every pedestal on my dock has its own dedicated conductors? Seems pretty inefficient if that's the case, and I don't see how it wouldn't be.
 
A comment was made that a lot of boats are made to take dual voltage 208 and 240. Not saying they are not, but of the medium priced 45 to 60 foot boats that I am familiar with that have larger AC units that require 240 or 208 are prone to this issue. Not sure of which ones you are talking about. I know that Jefferson, Hatteras and Prima were not. Maybe the new ones are, don't know that but mid 80's to early 90s are prone to this issue. I think the 208 was around at that time. So should we all be required to go out and buy different boats are spend thousand of dollars for these marinas. I guess that's what's being said. I just avoid the marinas if I can.
 
Egregious said:
So I'm on a metered pedestal but instead of having a small meter on the pedestal I have a house type meter on shore and I deal directly with the power company for billing. Does that mean that every pedestal on my dock has its own dedicated conductors? Seems pretty inefficient if that's the case, and I don't see how it wouldn't be.
Click to expand...

some meters have remote current sensors. Without a pix, can't be sure about yours.
 
answer in red.

O C Diver said:
Is there usually / always only one neutral on each side of a power pedestal? Most every 120V receptacle that I know of in this country contains a grounded current carrying conductor, commonly called a neutral; true for boats, homes, factories, etc. Not military ships though.

My boat has 50 amp 125 / 250 volt service. Everything in the boat is 120 volt. Occasionally I end up at a slip that has no 50 amp receptacle on the power pedestal. Sometimes the two 30 amp receptacles yield 240 volts, sometimes 208 volts, and sometimes 120 as they are on the same phase. The 208 or 240V should be OK, the same phase is NOT OK.
Your neutral conductor in the shore cable could attempt to carry 2 x 30 or 60Amps at full load The smart box adapters from either Hubbell or Marinco have a problem with 208 and go into error mode (they're fine on 240 volts). They also error if the two receptacles are on the same phase. sounds like your smart box is more clever than many experts!


Found an adapter that has two 30 amp males to a 50 amp 125 / 250 female without the smart box. It works very well. My only concern was whether both 30 amp receptacles in the power pedestal shared the same neutral and if they didn't, could that potentially be a problem? potentially.
Again, if you are bringing in 2x 30A of 120V at the same phase, the neutral currents add up. Your shore power white wire could run warm.

Ted
Click to expand...

edit: If your 50 Amp panel has a triple pole breaker, rated at 50A, then it will trip if neutral current exceeds 50A. Even if each hot line is only supplying 25Amps.
 
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I talked to the facilities mgr at port of Seattle yesterday day. He said that in the 60’s when the marinas were built they used wye and ran each leg up a different dock. The most you could get in those days was 50a 120v. It wasn’t until the 80’s that demand for 50a 125/250v started to show up but the need was for 100a 120v not 50a 240v so the just ran another leg of the wye up each dock. Starting in 00’s they started to get 208v complaints so they started replacing the wye’s with deltas. Now most but not all docks are 50a 120/240v. He also said that the original 60’ slip dock still is wye and they put a lot of transients on that dock so they can ignore the power complaints.
 
diver dave said:
answer in red.



edit: If your 50 Amp panel has a triple pole breaker, rated at 50A, then it will trip if neutral current exceeds 50A. Even if each hot line is only supplying 25Amps.
Click to expand...

Yes, my breaker panel has a 3 pole 50 amp main breaker. Thanks for your response!

Ted
 
Not exactly right on the neutral. The breaker will not trip if both hot legs are at full capacity. Any 230 volt loads do not use the neutral wire at all and any 120 volt loads will only load the neutral with the difference between the two legs.
On a 50 amp circuit using 20 amps at 230 and you use 25 amps of power on the black leg at 120 volts and 30 amps of power on the red leg at 120 volt 25 of those amps are cancelled in the neutral and the neutral is only carrying 5 amps.
 
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On a 50 amp circuit using 20 amps at 230 and you use 20 amps of power on the black leg at 120 volts and 30 amps of power on the red leg at 120 volt
Click to expand...
But that's not operating at capacity..
 
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