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Old 29-01-2017, 12:32   #31
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Re: Convert from 240 VAC to 120 VAC

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Originally Posted by a64pilot View Post
Your right, but as an aside note the current and or power will be cut in half, that was why I was trying to get across, it may not be safe to run a hair drier, toaster or other high power appliances, or it may be, depending of course what was available. 1500 watts or there about is about all you can normally pull out of a single circuit, usually I think?
If so and you cut the voltage in half, you can now only safely pull 750 watts, and a hair drier I think exceeds that?
Transformers like we used when I was in the Army to run our US 120 VAC stuff are not that expensive.
I brought a Germany Army Hatz Diesel 4 or 5 KW generator back with me, used a big transformer to run things and it was fine, got to think what would be different about a boat?
Plus why change anything to the boat is you don't have to? Don't have to change all the receptacles etc.

I would get another transformer with the idea of placing it on the dock inline with the shore power cord, I don't think I would want it in the boat.

Actually, the current will be 1/2 and hence the power 1/4, when you are talking about heaters. Motors are not quite that simple, depends on the application.
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Old 29-01-2017, 15:21   #32
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Re: Convert from 240 VAC to 120 VAC

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Originally Posted by dpeel View Post
Hot water heater should be simply a new element.
Perhaps not. Most of the small marine water heaters have 1500W elements, which is almost half of the power available on a 120V/30A circuit. If you wish to continue with 1500W you will need to swap the element, but consider this: if you are going to want to heat the boat electrically in winter climes then you won't have enough power to also run the water heater (on 30A). If you leave the 240V element in place the power consumption on 120V will be only 1500/4=375W, allowing more loads for other things like space heaters. Of course this means it will take 4 times longer to heat water, but if there is enough tank capacity for a couple to shower then this may work well. You may also wish to consider a 750W element. Something to think about anyway.

My recommendation for the overall project is that you read the ABYC standards for the electrical system, and follow them. If you find them to be over your head technically then you need to get a qualified marine electrician to do the job. Doing something like this from the seat of your pants with online advice is a really bad idea that can have seriously bad results.

Greg
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Old 29-01-2017, 16:42   #33
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Re: Convert from 240 VAC to 120 VAC

The more I think about this the more I realize that you will need to at least review the entire AC electrical system. If of adequate size the wiring should be re-usable, as the ABYC standards include the EU color codes. A few devices may be usable, but mostly not. You will likely need to add new devices to the system.

Current standards call for an ELCI (ground fault plus twin breaker) near the power inlet. Also either a galvanic isolator or isolation transformer is required. Personally I have chosen to add a transformer with windings and taps that allow either 120/240 on input and output, so if I go back to a 240V country I can continue to operate the equipment on the boat on 120V. While dealing with the power inlet, if the existing fitting is appropriate then also check for any corrosion or pitting on the contacts while checking conductor size.

My point is that you should not expect to change out a few things and be good to go - at least to current standards in the US. So again, either read and understand the ABYC standards or get a professional involved.

Greg
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Old 29-01-2017, 20:37   #34
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Re: Convert from 240 VAC to 120 VAC

The victron auto ranging transformer will input 120v, 220v and output either 120v or 220v depending on jumpers.

Boat will then work properly everywhere except for washing machines and Microwaves.

Great for world cruising and no other changes needed for many pieces of equipment.

Also get the benefit of the isolation transformer.

My Oyster 55 was built in 1990 and yes it was fused to the wire, however, going to 110v with the same wire often means pulling new wire of larger Guage.

Go with a parallel system for 110 and keep the 220v system running off the transformer.

Works well for me as a full time liveaboard.

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Old 29-01-2017, 20:44   #35
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Re: Convert from 240 VAC to 120 VAC

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Originally Posted by dpeel View Post
Wow!
Thanks for a great response!
The boat is a 2005 vessel built by Sweden Yachts. I am hoping that the wire size will be suitable for 120 Vac.
The boat will be based in the US permanently (with some distance cruising also) and therefore probably makes most sense to convert since only the battery charger and hot water heater are on 240V (apart from outlets). Hot water heater should be simply a new element.
I will investigate further when I get back on the boat in a few weeks time.
I do like the thought of using an inverter also - this gives more options.
Thank you for all your thoughts and suggestions - I will need to think these all through! I did check out the previous threads referenced and it certainly sounds like same debate
Thanks all!
Ahhhh, with only those two, convert to 110v and pull larger wire to those two points.

Keep the right sized fuse on the service outlets. If you find you need a larger one somewhere pull a new wire if necessary.

Also, most European boats have an ELCI (a big gfci) you may have to replace it for 110 operation. While it is a current measuring device, it pulls power from the lines to trip the switch.

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Old 30-01-2017, 01:37   #36
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Re: Convert from 240 VAC to 120 VAC

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I don't agree with this.
A 51' cat with 26' beam (switch 51 in your signature) is already in the big slips (or T head), so yes, they will typically have the larger shorepower outlets available because those slips are geared toward bigger boats with higher power needs.

For a typical 30-45' slip, they often have only the 120v 30amp shorepower available.

A dual voltage charger is fine but if the boat will stay in the States (as the OP indicated), it's makes more sense to just convert to 120v-60hz and be done with it.

Also, trying to maintain 220v-50hz appliances is silly if the boat is going to be permanently based in the States. Eventually they will fail and now you may have a mishmash of voltages and outlets. If it was just for a year or two, I would agree but for the OP's permanent situation, it doesn't make sense.
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Old 30-01-2017, 04:56   #37
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Re: Convert from 240 VAC to 120 VAC

We just solved a very similar problem on our boat. Our Taswell 43 was made for Asia, and wired for 230v 3 WIRE(not 4 wire 220v systems like the US uses!) power. After several false starts we bought and installed the Victron auto sensing isloation transformer....end of problem! It's quiet, not hot(but warm at near full load), and works! Now, no matter what the marina offers for power (110v-30amp, 110v-50amp, 230v-16amp, or 230v-32amp) we can plug in, the transformer IDs the power in and provides both isolation and 230v output, and use the boat as she was built. I also took one of the 230v outlets and wired a 220v to 110 volt, 1500w transformer to it, and then installed a handful of 110v outlets around the boat-----so we can use a few 110v things too! The system works perfectly.
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Old 30-01-2017, 10:36   #38
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Re: Convert from 240 VAC to 120 VAC

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Originally Posted by valhalla360 View Post
A 51' cat with 26' beam (switch 51 in your signature) is already in the big slips (or T head), so yes, they will typically have the larger shorepower outlets available because those slips are geared toward bigger boats with higher power needs.

For a typical 30-45' slip, they often have only the 120v 30amp shorepower available.

A dual voltage charger is fine but if the boat will stay in the States (as the OP indicated), it's makes more sense to just convert to 120v-60hz and be done with it.

Also, trying to maintain 220v-50hz appliances is silly if the boat is going to be permanently based in the States. Eventually they will fail and now you may have a mishmash of voltages and outlets. If it was just for a year or two, I would agree but for the OP's permanent situation, it doesn't make sense.
I don't think any marina does not have 220 power. So if you come across the rare marina where 220 is not available, you use two 110 plugs. A smart Y will combine the two. Converting to 120/60 is actually more difficult - new charger, plugs, wiring etc. Far easier to leave it at 220 and just add an inverter and a few outlets, and you can use all your normal appliances. That's it. That's what we did and it works great. Plus if you go overseas (or even to some of the islands in the Carib) you are ready for their shore power as well.
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