208volt Problem at Marinas

[caltexflanc]

If you have isolation transformers on your boat, you should see if they are tapable. Quite a bit of discussion on this at The Hatteras Owners Forum if you search the archives. The OEM transformers on the Hattes allowed you to put a switchable tap in place and you could boost voltage 10% when switched. A lot of owners did this on a DIY basis, putting the switch on the panel with the voltmeter. Just have to remember to turn it off when you leave for the next dock, and to keep an eye on voltage in case it is a matter of being erratic due to loads or permanently low.

 

[tiltrider1]

I would go the direction of a 208/240 step up transformer. You would need an automatic voltage sensing switch to bypass the transformer when you are on the generator or at a 240v dock. Easy and simple except for the cost of the transformer.

Diver Dave probably has the right idea. I have not really researched the idea so I can’t say weather to go with just a transformer for the ice machine or the whole boat.

 

[diver dave]

You dont want to do the entire boat. Only the “real” 240v loads. If you did the entire boat, the 120v loads get now 132v nominal. Its messy, but you want to divorce only the 240v loads and make it an option to boost only those 15%. And i would want automatic.
As you switch from gen to shore it requires yet another step if its manual.

 

[diver dave]

More bad news. If these 240v appliances also need 120v for controls/lights it gets very messy.

 

[tiltrider1]

More bad news. If these 240v appliances also need 120v for controls/lights it gets very messy.

Why Dave, the appliance is only going to see 240v and will step down to 120v internally if needed, or 12v if that’s needed.

Based on diver dave’s Concerns it appears the simplest solution is to just step up the ice machine. Stepping up the entire 240v side of the boat is going to require some rewiring of the panel. It can be done easily enough but will take a good chunk of time and more wire.

If stepping up the whole boat, each hot leg will be split right after the main breaker. One split to the 120v panel, the second split to the step up transformer. Same for the other hot leg. The 240v breakers will have their feed line removed from each side of the 120v panel and rerouted to the transformer. Some were in their will be a voltage sensing switch that can bypass the step up transformer if the transformer doesn’t have it built in.

 

[diver dave]

Why Dave, the appliance is only going to see 240v and will step down to 120v internally if needed, or 12v if that’s needed.

Based on diver dave’s Concerns it appears the simplest solution is to just step up the ice machine. Stepping up the entire 240v side of the boat is going to require some rewiring of the panel. It can be done easily enough but will take a good chunk of time and more wire.

If stepping up the whole boat, each hot leg will be split right after the main breaker. One split to the 120v panel, the second split to the step up transformer. Same for the other hot leg. The 240v breakers will have their feed line removed from each side of the 120v panel and rerouted to the transformer. Some were in their will be a voltage sensing switch that can bypass the step up transformer if the transformer doesn’t have it built in.

As you say for a straight 240V item. If that item has a neutral run to it, and if it also requires 120V, the story changes significantly. Why, because when you increase the hot leg on each side of 208 to 230, you also increase the leg to neutral voltage from 120 to 132V. If the icemaker, for instance, doesn't use 120V, then no issue. Understand, though, that most household 240V users also need 120V to operate. Water heater being an exception.

 

[tiltrider1]

Yep, your right, I was watching football and I brain farted. So if the ice maker uses 120v internally then best option would be to take a 120v and step up to 240.

 

[boater3]

A 208 Wye Transformer can deliver 120V from all three phases. We alternate each set of power towers red black white, blue black white and blue red white for load balancing and to supply phased 208V to every tower on every 3 phase breaker.


I only design floating docks so a 240 Delta is a non starter so we only design in 208 wye.

Hi I am at a dock that I think has 208 three phase Wye. I am experiencing 198-205 voltage. Certain items really crave 240v. When I run on generator those items work fine but they are getting the higher voltage.

Can you please clarify what you mean by alternating each set of power towers? What are the options to get say 230-240v to a tower if the marina is three phase Wye? Are the only options for the marina to install their own transformers on the docks? Can the power company do anything? Can I buy something for just my boat?

Thanks.

 

[boater3]

You dont want to do the entire boat. Only the “real” 240v loads. If you did the entire boat, the 120v loads get now 132v nominal. Its messy, but you want to divorce only the 240v loads and make it an option to boost only those 15%. And i would want automatic.
As you switch from gen to shore it requires yet another step if its manual.

Ugh, I was just thinking I could fix my 208v three phase Wye issue by buying a booster that plugs in-line on the 50 amp connection at the pedestal and sits on the dock. But my boat does have 120v loads/appliances/outlets. So what are my options now?

 

[Turtle Blues]

Search Larson Transformers. They List a few on Amazon. Not housed to sit in the environment. Meant as a permanent installation and not inexpensive.

 

[Duke 239]

Revived seven year old thread, nice!

 

[Turtle Blues]

The sad real world part is it is getting worse not better.
A marina due to location is usually at the end of a distribution leg, then you have the question of their transformer capacity, then the dock distribution runs, then the ever increasing power demands of the vessel at the end of the line....
And it's not even July yet. Might as well purchase a replacement set of cord ends before you need them, but that's another thread all by itself.

 

[boater3]

Would something like this work? Bridgeport Magnetics - Marine Isolation Transformers, Boat Transformer, Marine Magnetics Products

pros/cons?

 

[tiltrider1]

What you need is a boosting transformer. Unfortunately you will then have too much voltage when you get to a standard 240v dock. So what you need is an auto boosting isolation transformer. I have not researched this subject in a long time so I have no idea what is available.

 

[sunchaser]

Ugh, I was just thinking I could fix my 208v three phase Wye issue by buying a booster that plugs in-line on the 50 amp connection at the pedestal and sits on the dock. But my boat does have 120v loads/appliances/outlets. So what are my options now?

What is power at pedestal?measure with no cord in place.

Have you discussed this with your Marinas power supplier? BC Power supplies our Marina’s power. I talked with them many times about our (no problems) 208 dock power and came away with a greater understanding as to how it works.

 

[twistedtree]

Would something like this work? Bridgeport Magnetics - Marine Isolation Transformers, Boat Transformer, Marine Magnetics Products

pros/cons?

For what it's worth, ABYC requires that isolation transformers meet the requirements of UL 1561. I can't find anything that says the Bridgeport devices meet that standard.

 

[twistedtree]

Ugh, I was just thinking I could fix my 208v three phase Wye issue by buying a booster that plugs in-line on the 50 amp connection at the pedestal and sits on the dock. But my boat does have 120v loads/appliances/outlets. So what are my options now?

THere is another similar thread running and I just posted over there about the two ways you can solve this. Ward's offers a stand along, plug in boosting transformer. It's not cheap, but it's probably cheaper than replacing your isolation transformer with one that has 208 boost capability.

Note that iso transformers with automatic boost are available and very expensive - order $10k. They detect the voltage and automatically switch between 208 and 240V input. You can do the same for much less $$ with a manual switch that just changes which transformer taps are used, and manually select the setting when you plug into a dock.