Boost Volts from 208 to 230

[Seevee]

What would one need to boost the power at a marina that's low, ofter 208 volts or 104 volts, when you need 240 or 120?


What transformers are available that will do this boost?


Note: I have one on my Mainship, a Charles 93-IXFMR12I-A Isolation Transformer.


However, it's a big clunky thing and shopping for another boat that doesn't have a transformer.



Solutions?

 

[garmstro55]

I posted my solution here: https://www.trawlerforum.com/forums/s11/ms400-low-dock-voltage-~100volts-solution-51268.html

I found it on the Red Pearl site and did the same thing. It works!

 

[jhall767]

I installed one of these on my boat. It will boost or lower the voltage as needed automatically.
https://angconverters.com/ang-boost-2/

A boost transformer will protect against improper 208V transformers,
reverse polarity and the new GCFI pedestals.

 

[caltexflanc]

Isolation transformers are something you want to have no matter what the issue you have with their "bulk".

Two solutions have been shown here. The Iso-Boost (formerly marketed by Charles prior to their exit from the marine industry) is the most expensive and elegant and no-brainer, as they automatically sense the need, and then lack of need. We had them on our old Hatteras compliments of the PO. Wonderful.

When you tap a transformer to create a switchable boost, it is very important to understand that it will boost every voltage level coming in, so leads to severe over voltage, say when you get to a 250 volt dock. So you need some sort of big red flag reminder to switch it off.

An in between solution is to get a "buck boost" transformer that you plug your shore power cord into and then plug the transformer into the dock outlet. Such as the one sold by Ward's. Scroll down to page 3. Bulky to schlep around, but more foolproof than the switched tap solution.

For it and the switched tap solution note bene the warning about using it at marinas with voltage variation issues. It is not always due to a 208v situation. You may be at the end of the dock, then a bunch of people down the dock show up and turn their air conditioning on start cooking a meal in their electric galley. We witnessed this in observing our Iso-Boosts switch on and off.

https://2486634c787a971a3554-d983ce...s-marine/media/transformers-5dcaa98d43a1c.pdf

 

[jhall767]

Isolation transformers are something you want to have no matter what the issue you have with their "bulk".

Two solutions have been shown here. The Iso-Boost (formerly marketed by Charles prior to their exit from the marine industry) is the most expensive and elegant and no-brainer, as they automatically sense the need, and then lack of need. We had them on our old Hatteras compliments of the PO. Wonderful.

When you tap a transformer to create a switchable boost, it is very important to understand that it will boost every voltage level coming in, so leads to severe over voltage, say when you get to a 250 volt dock. So you need some sort of big red flag reminder to switch it off.

An in between solution is to get a "buck boost" transformer that you plug your shore power cord into and then plug the transformer into the dock outlet. Such as the one sold by Ward's. Scroll down to page 3. Bulky to schlep around, but more foolproof than the switched tap solution.

For it and the switched tap solution note bene the warning about using it at marinas with voltage variation issues. It is not always due to a 208v situation. You may be at the end of the dock, then a bunch of people down the dock show up and turn their air conditioning on start cooking a meal in their electric galley. We witnessed this in observing our Iso-Boosts switch on and off.

https://2486634c787a971a3554-d983ce...s-marine/media/transformers-5dcaa98d43a1c.pdf

Quite right on the voltage. Can be too high or too low. And can change while you are away from the boat. My transformer cuts out when it get's too far out of range and it can't be corrected. It suspended power when the incoming voltage got over 260 and it couldn't drop it back to a safe level for the equipment.

 

[caltexflanc]

Quite right on the voltage. Can be too high or too low. And can change while you are away from the boat. My transformer cuts out when it get's too far out of range and it can't be corrected. It suspended power when the incoming voltage got over 260 and it couldn't drop it back to a safe level for the equipment.

Yes, that is one of the beauties of the Iso-Boost system. But 260 is fortunately a pretty rare occurrence on the American electrical grid. Just imagine having a constant boost solution even at 240 or 250.

 

[tiltrider1]

There is another option as well. You can take any circuit of 120v and use a transformer to turn it into 240. If you have 50a of 120v you will be limited to 25a of 240v. If this is sufficient you won’t need to worry about 208v or finding two 30a plugs that are out of phase. This method can be done with or with out isolation transformers.

 

[FF]

Remember any "boost" transformer will boost the amperage required from the power cord.

V x A = W so the voltage may rise , but there will be fewer amps to run your gear.

Sounds like the location is set up for 3 phase , not std house current?

 

[sunchaser]

What would one need to boost the power at a marina that's low, ofter 208 volts or 104 volts, when you need 240 or 120?

Many dock power installations are designed for 208. Ours are with no ill effects. It seems then that the question really comes down to is the 208 by design or by poor dock electrical installation?

If one's dock wiring is designed for 208 why bother with an IT addition to fix a non existing problem?

 

[Woodland Hills]

Many dock power installations are designed for 208. Ours are with no ill effects. It seems then that the question really comes down to is the 208 by design or by poor dock electrical installation?

If one's dock wiring is designed for 208 why bother with an IT addition to fix a non existing problem?

If the dock voltage is too low, our a/c will not run. It just throws a “low a/c” code. Plugging in the boost transformer gets the boat cooling again.

 

[Seevee]

Great info, thx.


Yes, the issue is mainly with the AC unit. I've never had an issue with high voltage, only low volts. However, I've found it quite common, perhaps 15 to 20% of the marinas I've patronized.



Some motors and circuit boards could be damaged with low voltage, so want to keep it close.



I do have the Charles transformer on my current boat with a mod that boosts the voltage which works great, but shopping for a different boat.

 

[Choices]

A voltage swing of 10% is allowed. Typically 208 is done to balance an electrical circuit.

Your isolation transformer may have taps you can change. Some have 2) at 2.5% above and below nominal voltage. So that gives you a 5% boost by design.

You will have to change taps for different marinas...

 

[bayview]

208 is used in many industrial applications. It may be correct and standard at your dock and not indicate a problem. My boat ran close to the breaker limit with all ACs running and everything else going on 208 V docks. I didn't like it but it worked.
I was careful to check power cords for over heating. I just dont think things are meant to run at their limit for long.

 

[caltexflanc]

A lot of older equipment on boats, such as AC equipment is not designed to run on 208, and some, such as kitchen equipment don't work as efficiently. As noted by FF, energy is measured in watts. So if volts go down, an appliance that requires a certain wattage will consume more amps to work correctly.

One work around used at 208 marinas is to get a Smart Y and hook it to opposite phase 30 amp outlets, Resulting in lower amperage capacity but delivering full voltage. We used ours on a few occasions when no 50/250 outlet was available typically for one transient night. We didn't enjoy managing loads, Ann once asked me why I hadn't bought two of them; I replied that the marinas typically frowned on one boat using four outlets. The Mainship 430 we used to charter supplied one as well, and there were places up in the Delta where it came in handy. But if there aren't two out of phase outlets, then the only choice is to turn on the generator, seldom a popular move in marinas with a lot of people on board.

 

[jhall767]

I don't know where some if this information is coming from but unless you are running three phase 208V is not correct. The marina may be wired that way but that is because the wrong (cheaper) transformer was installed. The 120V circuits are fine. It's only the 240V that doesn't work properly.

208V is the three phase voltage rating. There are three 120V legs or phases that are 120 degrees apart and the "voltage" between any two legs is 208. A/C equipment can run on that but it not the same as low voltage on a 240V circuit in which the two 120V phases are 180 degrees apart. It is not as efficient which also causes a larger current draw in addition to the lower voltage.

In the US the utility companies are required to provide 240V as the primary circuit for residential use.

 

[caltexflanc]

I don't know where some if this information is coming from but unless you are running three phase 208V is not correct. The marina may be wired that way but that is because the wrong (cheaper) transformer was installed. The 120V circuits are fine. It's only the 240V that doesn't work properly.

208V is the three phase voltage rating. There are three 120V legs or phases that are 120 degrees apart and the "voltage" between any two legs is 208. A/C equipment can run on that but it not the same as low voltage on a 240V circuit in which the two 120V phases are 180 degrees apart. It is not as efficient which also causes a larger current draw in addition to the lower voltage.

In the US the utility companies are required to provide 240V as the primary circuit for residential use.

Thanks for articulating, all are points well taken.

 

[sunchaser]

To add a bit more. In a 3 phase circuit 208 volts is the line to line voltage. Whether at marinas or lesser electrical use businesses this 3 phase voltage is frequently used. But the line to neutral voltage is 208/1.732 (square root of three) or 120 volts.

So Seevee, is your marina power 3 phase? Our 208 volt marina in BC has never given us any trouble.

 

[FF]

In some cases the "marina" was a working boat yard so 3 phase would be chosen to power motors.

Not the best for 120/240 use , but some equipment will survive .

The correct transformer is worth the effort. google the methods.

 

[boater3]

I need to get 208v boosted to 230-240v.

I have a Charles 93–IXFMR12T–A. The manual does show something that says "boost" but there is no other information. I dont know that my model has that capability.

I am looking for either a portable boost transformer or a Charles alternative (who is making a quality product)?

Also, does it matter if the 208v is single or three phase? Delta or Wye?

 

[Delta Riverat]

You want an autotransformer, not an isolation unit. Much smaller and much cheaper. The whole load doesn't need to go across the core, just the boost.

 

[tiltrider1]

The reason the power is 208 has to due with you getting two power feeds of a Y transformer were each feed is 120 degrees out instead of 180.

I think you would be well served to seek some one on one education on this subject.

 

[fgarriso]

They are not cheap, but Atlas frequency converters will handle 60 to 50 hertz and high or low voltage.

 

[boater3]

Would something like this work? https://www.bridgeportmagnetics.com/bmg-product/marine-isolation-transformers/

pros/cons?

 

[tiltrider1]

Would something like this work? https://www.bridgeportmagnetics.com/bmg-product/marine-isolation-transformers/

pros/cons?

These will simply pass on 208v if that is what is on the dock. There is a way to wire them such that you don’t get two 104v legs but two 120v legs. You could then take one of the legs and boost it to 240v. You can not use both hot legs to get 240v, you will just end back at 208v.

Boosting one leg to 240v might not get you enough amperage to run all your 240v requirements.

 

[Turtle Blues]

There is always a solution. Cost is always a factor.

 

[boater3]

These will simply pass on 208v if that is what is on the dock. There is a way to wire them such that you don’t get two 104v legs but two 120v legs. You could then take one of the legs and boost it to 240v. You can not use both hot legs to get 240v, you will just end back at 208v.

Boosting one leg to 240v might not get you enough amperage to run all your 240v requirements.

This is what they said:
"For 50A input (up to 12KVA load) use dual MP6.

Interconnect striped Black and striped Yell primary leads.

At 208V input between striped White and solid Orange you get 240V or 120V secondary voltage.
At 240V input between striped White and Striped Red, you get 240V or 120V secondary voltage.

Single or three-phase delta or wye makes no difference."

So thats just boosting one leg? The other solutions boost both?

 

[twistedtree]

There are two ways you can solve this problem.

1) Use an isolation transformer that have winding taps to accept either 208V or 240V input. Wire with a switch to select which input to use. This will be the hardest fix, but the most integrated and easiest solution to use. Acme/Hubbell makes a good line of transformers that meet ABYC requirements and have such a feature, and could be installed in place of your existing Charles transformer. However I'm a bit surprised that the Charles doesn't have taps for 208V input. At least some of them do. Somewhere on the case there should be a sticker with a wiring diagram. Can you post a picture of that, just so we can be sure your existing transformer can't solve the problem. It looks like it's the 93-IFXMR12I-A that supports 208V

2) Add a boosting autotransformer between the shore power and your isolation transformer. This could be permanently installed in the boat with a selector switch, or can be external and plugged in as needed. This will bost the 208 dock power to 240 before it get to the onboard transformer. Ward's makes unit with handles and pig tail plugs that you can haul out and plug in as needed. I think this approach is the most cumbersome to use, but probably the least expensive.

 

[tiltrider1]

This is what they said:
"For 50A input (up to 12KVA load) use dual MP6.

Interconnect striped Black and striped Yell primary leads.

At 208V input between striped White and solid Orange you get 240V or 120V secondary voltage.
At 240V input between striped White and Striped Red, you get 240V or 120V secondary voltage.

Single or three-phase delta or wye makes no difference."

So thats just boosting one leg? The other solutions boost both?

I never looked at Bridgeport with the intention of solving a 208v issue. I didn’t remember there being a tap for boosting. If you are correctly quoting them then a manual switch could be added that would make it a boosting transformer.

The reason that Bridgeport does not meet ABYC standards is due to a lack of a grounding wire to the cover. Bridgeports cover is composite and is not conductive. ABYC admits that it needs to update their standard to include toroid isolation transformers.

 

[BLUE STEEL]

I need to get 208v boosted to 230-240v.

I have a Charles 93–IXFMR12T–A. The manual does show something that says "boost" but there is no other information.

Here is a the guide I followed, the reverse feed wiring instructions from Charles (circled in red), and a diagram I created. I see 235v on 208v shore power.

Hope this helps!

EDIT - My mistake, I have the 93-IXFMR12I-A. Different model.

 

[twistedtree]

I never looked at Bridgeport with the intention of solving a 208v issue. I didn’t remember there being a tap for boosting. If you are correctly quoting them then a manual switch could be added that would make it a boosting transformer.

The reason that Bridgeport does not meet ABYC standards is due to a lack of a grounding wire to the cover. Bridgeports cover is composite and is not conductive. ABYC admits that it needs to update their standard to include toroid isolation transformers.

The language that allows toroidal transformers, including those without shield grounds has been in the draft of E11 for a couple of years now, and visible to anyone who participated in the various public reviews. But for reasons unrelated to toroidal transformers, a new version of E-11 has not been released.

This was in the public review documents so I think OK to share, but understand that it’s not official until the standard has been approved, and it could change between now and then…..

In the draft, toroidals are allowed similarly to other encapsulated transformers. However they still must meet UL 1561. And to handle the lack of a shield ground, an RCD breaker is required in front of the xfmr.

I have not seen anything in Bridgeport’s literature saying the meet UL 1561.