In particular; Is there code or standards for the nominal voltage being supplied? In particular, it appears some (many) marinas don't even supply 240V single phase, but instead supply 208V nominal, since they are using WYE 208 systems dockside. Most yachts up to 70 ft or so are single phase, and it seems have to live with running 240v appliances at 208, which may or not work.

 

For better power distribution you are most likely to find 120/208v three phase service at the dock.

 

i expect this in 3 ph industrial settings. Problem being, many marine A/C systems in single phase boats are speced at 240, not 208. Same with water heaters and other large users.

How come the "better power distribution" isn't at play with homes? I suppose my target is the marina's for putting in cheap(er) sytems that shortchange voltage rqmts. Glad my utility doesn't have this same attitude for my house...

 

You and your neighbors have a dedicated 120/240v single phase transformer because you are close to the distribution lines. In a marina there are long distances between the primary supply and the secondary user. Not to mention the savings of wire using a three phase system.

Marinas are subject to the same problems as campgrounds. The cost of extra and larger wiring.

 

Let's say the marina does the boater right and puts in single phase 240/120 transformers in place of the existing 3 ph WYE. My secondary runs of cable are the same length. In fact, there is only a need for a single HV phase to be run, not 3. I'm not seeing it yet.

edit: maybe my more basic question is if the primary line loss is significant? Are they running 13kV up and down docks or closer to 600V?

 

found this dockside 150kva device:

Marina Electrical Equipment -GTX? UNIT SUBSTATION

looks like it is 600V 3 ph feed. So, if there is an efficiency or voltage drop or cost issue, its at the primary side. Maybe docks are limited to 600V??

 

It is very rare that I have seen equipment that will not run fine on 208. Especially resistive load such as water heaters should have no issues other a slightly lower output. There are no code requirements for the power to be supplied. It is typically designed based on the requirements of the installation.

A marina is basically a business, and if available, will have commercial power. Because of efficiencies and costs it would make sense for it to be 102/208 3 phase. The power company normally provides the transformer(s) for the service. I see no benefit of a 600 volt transformer "sub station"

Marinas are covered in Art. 555 of the NEC. Only voltage limit I saw is 1000 volts.

If a boater really wants 120/240 they should provide their own 208 to 120/240 volts transformer.

 

Here is a report:

"Well...
one marina I did work on had a huge voltage problem at the end of a 700 foot dock. There were lawsuits filed for substandard power being supplied to the slips from the marina. Owners were having to replace AC units at $5-7K each and the charter boat that goes on 3 day trips was replacing it's ice making machine compressers monthly.
We were able to step up the output of the substation and install a larger length of 200 foot cable at the end of the run to help with the drop. (the marina was built under the 1999 code so splices weren't near the issue they are now) When the dock tenants started getting the 230-240 volts at their docks, the lawsuit was dropped.

Is there a way to reduce the amount of W cable installed? If there is a continuous run of conduit you may be able to use THWN and save money there.

another:

"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."

a third report:

"My boat's ice maker (not for cocktails, but to fill the fish holds) won't run on 208, which is what my slip provides and is fairly common in California and west coast of Mexico, in my experience. It runs fine on my generator (240 volt), but I prefer to run it for a day ahead of time to have plenty of ice when I depart. It has been suggested that I install a buck transformer (steps 208 volts up to 240) on my dock. Now I just need to find the right transformer at the right price."

Pretty dissapointing to see designs that target a nominal of 208 to feed 240V a/c, icemakers, etc. There are NO boats that need or want 208. Really big yachts use 3 ph 480V.

 

Just curious.... where are we going with this ?
Are you a power user are are you designing a system.

 

I'm in the power transmission industry, but just getting my feet wet on marina power. Looking to find out how it comes to pass that these crappy designs become acceptable. ie; 208 nominal desgins to feed 240V equip, up and down both coastlines into Canada.

ps: who here would accept 208/120 into their homes??

 

Oh... I could have told you that...... it's all about the money.

 

It's reasonably common in multi tenant apartment/condo complexes... It seems like keeping a buck/boost transformer around would be the best way to deal with it on the gear that really needs 240V.

 

This case sounds more like design problem as in the design engineer didn't have a good handle on the anticipated and calculated loads. Voltage really shouldn't drop appreciably if the transformer is sized properly and if the voltage doesn't drop, no one would be the wiser, 208 volts is normally adequate. Some transformers also have taps that be changed or adjusted to boost the output voltage.

 

I suppose my expectations are too high. I travel a lot (not by boat) and I expect something like a hairdryer and shaver to work in every hotel room in the country, and so far, so good.

So, lets say your POCO has found some way to save $ and all of a sudden your service is now two legs of a 208V system. Your A/C compressor burns up. You complain to the POCO. POCO says you now need to buy a auto-transformer for all your 240V needs. I think there would be an uprising against the POCO by a large segment of the population.

From a boaters perspective, they also hope for some consistency from marina to marina, certainly in the same country! But, no, there is not. Many have 208, many have 240. Most don't even know. Its a mess and invariably, the boater looses.

 

This is mostly for my own curiosity, but is there a shore power standard out there (ANSI, NEMA, etc) that these marinas are failing to meet or trying to circumvent? Or is it a situation where there is history / tradition / general agreement about what shore power should be, and various marinas do it differently?

 

I was trying to find that out but there isn't too much on protocall.
It seems that the marina wires as it sees fit.

 

You may be shocked at what boaters are having to do to "plug-in". Most are armed with various adapters, Y's and extension cords. Boats can have 120V 30 A inlet, two 120V 30A inlets, a single 50A 120V inlet, a single 50A 240/120V inlet, and very large yachts will have 480V 3 phase inlets. Of course, all these are different styles of locking connectors. A very popular adapter is a "Y" adapter. This enables a 50A boat to use 2 x 30A shore recept. But, those two shore HOTs could be two legs of 208, or both sides of a 240, or the same phase of 120V. If it's 2 x 120, then they face up to a 60A neutral current. Many wander around the dock, testing various 30A recepts to find two that are on different hot legs.
Some 50A boats have only 120V loads, but some have both 120 and 240, using the same inlet connector.

Far more extreme trying foreign recepts, even at 60Hz. But, the problem described above exists on both US coasts, up to and including canada.
New dock power designs are doing 240/120 and 208/120. Using the same recepts...
It's a mess.

 

If you are using a 208 volt to 240 volt step up transformer then if the 208 volts suffers brownout conditions (say 5% down, down to 198 volts), the transformer will still deliver brownout conditions but this time it will be 240 volt brownout conditions that are not so bad for 240 volt appliances, namely 228 volts when the incoming 208 dropped to 198 volts.

Brownouts happen when several boats are drawing lots of power at the same time and the line strung down the marina is not heavy enough. You need to be careful about using a tapped transformer turn brownout 208 into non-brownout 240 (198 to 240) because the voltage already coming down the line might already have been jacked up resulting in above standard voltage during low load times. THen your jacking up the voltage a little more for good measure could result in an excessively high final voltage.

 

Sounds to me like a lack of standardization among the boat manufacturers. There are just too many possible configurations for any marina to try to accommodate all configurations at all slips.