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Old 24-07-2016, 10:54   #31
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Re: Converting from 220 volts to 110

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Originally Posted by Cottontop View Post
So there have never been electrical fires, because circuit breakers never fail?
I'll go out on a limb and state that 95+% of electrical fires are NOT caused by circuit breaker failure. (I'm sure someone will argue the number!) In fact, the typical failure mode for a circuit breaker is tripping on less current than designed. Since I can start a fire with <1amp of current, the majority of fires are due to appliance failure or faulty wiring. Circuit breakers protect wire from overheat due to too much current draw, they don't protect against all appliance faults nor poor connections in the wire.

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Properly sized circuit breakers are important. Properly sized wires are even more important. And if you reduce the voltage serving a load, you may need to increase the wire size to accomodate the increased amperage. Simply relying on the circuit breaker is foolish. And if the first time you fully load something (the autopilot, say), you're at sea, and now the circuit breaker starts tripping, now what?
Your autopilot operates on AC?

I suggest you use fuses if you don't trust circuit breakers, I'll continue to use breakers.

Appliances must be able to operate on both voltages, one simply does not just reduce the voltage and see what happens. Exceptions to this is the heating element in most marine hot water heaters, they don't care about voltage, and btw, they run @~25% power on 120v vs. 230v, hence, no problems with a hot water heater needing bigger wire. If your 60amp shorepower battery charger is rated for 100-240v 50/60hz, yep, it'll pull ~8a on 120v whereas only ~4a on 230v. Not sure I've seen dual voltage AC units.

The problem with these threads is people think they'll burn their boat down by reducing the voltage on a circuit. As long as the wire size and breaker are matched during installation, it's perfectly safe to lower the voltage. The lower voltage circuit won't deliver as much power, but it doesn't mean it isn't safe. To state otherwise is doing a disservice to the cruising community. If a circuit won't deliver the power required after lowering the voltage, then new circuit design is required. Circuit design includes both wire size and breaker.
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Old 24-07-2016, 11:00   #32
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Re: Converting from 220 volts to 110

Bought my beneteau 51.5 Cyclades in 2012 in bvi she was a euro boat 220v but equipped with a transformer for the power outlets in the boat. Have been all over the Caribbean with no issues just changing the male plugs for the doc boxes to euro plugs for the French and ABC Dutch islands also Grenada marinas. Presently in st Croix I'm plugged in in a regular 250v US outlet. Interestingly the AC on the boat is cruise air both 110 and 220 so no problem just changing the male plug from euro to US
Don't worry it's easier said than done.
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Old 24-07-2016, 11:03   #33
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Re: Converting from 220 volts to 110

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As long as the wire size and breaker are matched during installation, it's perfectly safe to lower the voltage. The lower voltage circuit won't deliver as much power, but it doesn't mean it isn't safe. To state otherwise is doing a disservice to the cruising community. If a circuit won't deliver the power required after lowering the voltage, then new circuit design is required. Circuit design includes both wire size and breaker.
A 1500 watt kettle, for example, uses twice as much current on 120 volts as on 240 volts. It is current that both wire and breakers are sized for, not voltage.

As I posted, it depends how the boat was originally wired.
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Old 24-07-2016, 11:17   #34
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Re: Converting from 220 volts to 110

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Originally Posted by mitiempo View Post
A 1500 watt kettle, for example, uses twice as much current on 120 volts as on 240 volts. It is current that both wire and breakers are sized for, not voltage.

As I posted, it depends how the boat was originally wired.
, a 1500 watt kettle built for 230v service will draw 6.5a when on 230v. That means it's heating element is a resistive load of 35ohms. This equates to 3.4a when plugged into 120v which is ~400 watts of power. Your kettle will take much longer to heat water, but only requires half the current on the lower voltage.

It's simple Ohms Law!

(Kettle/resistive heat appliances are not good examples for your argument)
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Old 24-07-2016, 11:21   #35
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Re: Converting from 220 volts to 110

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, a 1500 watt kettle built for 230v service will draw 6.5a when on 230v. That means it's heating element is a resistive load of 35ohms. This equates to 3.4a when plugged into 120v which is ~400 watts of power. Your kettle will take much longer to heat water, but only requires half the current on the lower voltage.

It's simple Ohms Law!

(Kettle/resistive heat appliances are not good examples for your argument)
And you have a 120 volt 400 watt kettle? Mine is 1500 watts.
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Old 24-07-2016, 11:31   #36
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Re: Converting from 220 volts to 110

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And you have a 120 volt 400 watt kettle? Mine is 1500 watts.
Like I stated, if your kettle is 1500 watts on 230v, it'll be 400 watts when connect to 120v. If your kettle is 1500 watt on 120v, please don't connect it to 230v as it will most likely fail in an ugly fashion, like catch fire, as it is now close to ~5500 watt kettle (breaker should trip first)!
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Old 24-07-2016, 11:39   #37
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Re: Converting from 220 volts to 110

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The easiest solution is to install a transformer to step up the 110V US power to 220V for the on board circuits. Then you have to deal with any built-in components (battery charger, A/C, frig, etc.) to see if they can be run at 60hz. If not they will have to be replaced or discarded before you connect to 110VAC 60Hz shore power.

Of course once you get the boat to the US you will no longer have convenient access to purchase new or replacement 220VAC electrical components, but at least you will have a boat with a working and safe electrical system. Well, at least as safe as it was on European power.

There are many manufacturers of transformers - Mastervolt, Charles, etc. Most can be wired permanently between the shore power receptacle and the distribution panel such that it will work fine while still in Europe and will accommodate 110VAC power by throwing a switch on the transformer.

Still it is not a simple problem, and your asking the question implies you are not that familiar with AC power at any voltage. I suggest you use a qualified marine electrician to evaluate any boat you are considering for puchase to determine the level of effort required to make it functional and safe on 110VAC60Hz power.

John
Probably the best advice I have seen. And didn't buy into that cycle nonsense. It you have fans with synchronous motors they will run faster and that is about it.
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Old 01-09-2016, 12:14   #38
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Re: Converting from 220 volts to 110

Can't you take 220v, without the neutral, from the US shore power and connect it to the 220v European boat. I've seen European boats take their shore power plug and put a 220v 50A 4 wire plug on their cord end and not use the neutral. 220v is 220v .

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Old 01-09-2016, 13:14   #39
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Re: Converting from 220 volts to 110

Just out of curiosity are we trying to mix three phase and single phase? What is supplied in Europe?
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Old 01-09-2016, 20:12   #40
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Re: Converting from 220 volts to 110

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Can't you take 220v, without the neutral, from the US shore power and connect it to the 220v European boat. I've seen European boats take their shore power plug and put a 220v 50A 4 wire plug on their cord end and not use the neutral. 220v is 220v .

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the 24O volt US split phase is 60hz. the 230v euro single phase is 50 hz.

some things will run on either freq. many will not. some will blow up.

220v is not a thing.
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Old 02-09-2016, 03:29   #41
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Re: Converting from 220 volts to 110

I realize the Hz problem, but an appliance doesn't care if the 220v is split phase or single phase. If you order say a Yamaha 5kw generator and look how they wire it for 220v 50Hz, they just lower the RPM and use 220v without the neutral.
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Old 02-09-2016, 07:29   #42
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Re: Converting from 220 volts to 110

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Like I stated, if your kettle is 1500 watts on 230v, it'll be 400 watts when connect to 120v. If your kettle is 1500 watt on 120v, please don't connect it to 230v as it will most likely fail in an ugly fashion, like catch fire, as it is now close to ~5500 watt kettle (breaker should trip first)!
You're math is right, but you're missing an important point.

1500 watts is a popular power for a kettle. Therefore, there are lots of kettles that are 220V and 1500 watts. There are also lots of kettles that are 110V and 1500 watts. We like our kettles to get hot pretty quick, and not wait around all afternoon. So 1500 watts it is.

Since, as you know, power = voltage * current, the 110V kettle will require a much higher current to achieve 1500 watts.

This is fine, assuming your wiring is sized properly for that current. I think at this point we are in agreement.

But what you aren't seeing is that the wiring, the circuit breakers, everything on a boat were sized for the sorts of things people are plugging into them. 1500 watt kettles and whatnot. Nobody just added more copper than necessary for the hell of it. So its highly unlikely that when you drop down to 110 on a boat that was designed for 220, you are going to have the capacity you want in your circuits.

Lets do an example. A 220 volt boat with a kettle and a microwave.

Lets say you had a 15 amp circuit on your 220 volt system. This equates to 3300 watts of power capacity on that circuit.

You've got a 1500 watt kettle, and a 1500 watt microwave, and it all works great.
3000 watts of 220V appliances need 13.6 amps. We've got a 15 amp circuit (15 amp wires, 15 amp breaker) so we are cool.

Now you bring it to the US and want to wire everything for 110V. Since you don't want to wait 2 hours for your old 220V kettle to heat up at 110V, you buy a new 110V, 1500 watt kettle. Since you want your microwave to function, and be as powerful as it was before, you buy a new 110V, 1500 watt microwave. But now you start blowing your 15 amp breaker!

You're 3000 watts of 110V appliances now need 27.3 amps. So while you are right, you won't burn anything down assuming you kept your breakers at the same amp level as before, you'll have a much less useful electrical system at 110V.

This is why its not at all unreasonable to factor in the cost of running new, fatter wiring when switching from a 220V system to a 110V system. Because at the end of the day, the watts you want to consume haven't changed.

If it were me I'd probably just keep it at 220 until appliances started to get old and break, then bite the bullet and switch over with new wiring (if necessary) and new appliances.
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Old 02-09-2016, 08:15   #43
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Re: Converting from 220 volts to 110

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You're math is right, but you're missing an important point.

1500 watts is a popular power for a kettle. Therefore, there are lots of kettles that are 220V and 1500 watts. There are also lots of kettles that are 110V and 1500 watts. We like our kettles to get hot pretty quick, and not wait around all afternoon. So 1500 watts it is.

Since, as you know, power = voltage * current, the 110V kettle will require a much higher current to achieve 1500 watts.

This is fine, assuming your wiring is sized properly for that current. I think at this point we are in agreement.

But what you aren't seeing is that the wiring, the circuit breakers, everything on a boat were sized for the sorts of things people are plugging into them. 1500 watt kettles and whatnot. Nobody just added more copper than necessary for the hell of it. So its highly unlikely that when you drop down to 110 on a boat that was designed for 220, you are going to have the capacity you want in your circuits.

Lets do an example. A 220 volt boat with a kettle and a microwave.

Lets say you had a 15 amp circuit on your 220 volt system. This equates to 3300 watts of power capacity on that circuit.

You've got a 1500 watt kettle, and a 1500 watt microwave, and it all works great.
3000 watts of 220V appliances need 13.6 amps. We've got a 15 amp circuit (15 amp wires, 15 amp breaker) so we are cool.

Now you bring it to the US and want to wire everything for 110V. Since you don't want to wait 2 hours for your old 220V kettle to heat up at 110V, you buy a new 110V, 1500 watt kettle. Since you want your microwave to function, and be as powerful as it was before, you buy a new 110V, 1500 watt microwave. But now you start blowing your 15 amp breaker!

You're 3000 watts of 110V appliances now need 27.3 amps. So while you are right, you won't burn anything down assuming you kept your breakers at the same amp level as before, you'll have a much less useful electrical system at 110V.

This is why its not at all unreasonable to factor in the cost of running new, fatter wiring when switching from a 220V system to a 110V system. Because at the end of the day, the watts you want to consume haven't changed.

If it were me I'd probably just keep it at 220 until appliances started to get old and break, then bite the bullet and switch over with new wiring (if necessary) and new appliances.
I'm not missing any point, as I've stated more than once in this thread (example from post #31 above):

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...snip... If a circuit won't deliver the power required after lowering the voltage, then new circuit design is required. Circuit design includes both wire size and breaker.
Again,

The typical EU 230v circuit will deliver (almost) twice the power as the same circuit using 120v. My point has been all along is there is nothing unsafe about lowering the voltage to 120v and using the existing circuit. The example scenario you lay out does not prevent the kettle or microwave from safely operating on the lowered voltage circuit asynchronously. (BTW, a common circuit in the EU is 16a, delivering 1920watts @ 120v)

Since 120v circuits in the US are typically (in the last 25 years) 20a, yielding 2400watts, one could not use a single US circuit for your scenario either, so how would you wire your scenario???? It requires 2 circuits @ 120v, a symptom of US electric code! But that doesn't prevent you from lowering the voltage on the existing EU circuit and operating up to 1920watts. So, it's not just bigger wire required, it's a new design IF the existing circuits won't cover your use case(s).
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Old 02-09-2016, 08:17   #44
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Re: Converting from 220 volts to 110

Based on what I've been told....do NOT use the US 220v (a 4 wire system, 110, 110, neutral, ground)) into a European 230v (a 3 wire system, 230v, nuetral, and ground) by bypassing the neutral wire in the US 220v system. By doing that you are using the ground wire for return current and not for the safety purpose it was/is intended for. Yes....it will work, but if there is a fault/short in the system......it's called FIRE! While the cycle difference needs to be addressed(motors-yes, resistance appliances-no, electronics-??) if the marina can not supply you with a 230v (or 240v) 3-wire supply, then you need to use a transformer to convert the 120v (3-wire) to 240v(3 wire) to use.....and keep the ground wire for safety-as it was intended.
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Old 02-09-2016, 08:19   #45
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Re: Converting from 220 volts to 110

Don't think I got an answer as to whether or not Europe was single or three phase. The reason for posing the question was going back to someone's question on polarity at a marina. Single phase your neutral and ground will be the same three phase it will not.
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