Step up transformer for US craising in a 220v boat

[Oscarpop]

We head to the US in a few weeks and are researching step up transformers.

Victron seem to be the fore runner , but their transformer won't convert the US 60HTZ to UK 50htz.
How much difference does this make?
We power mostly computers and a TV with our power, so I thought that they would both be ok with a 60htz supply?

Any thoughts?

 

[Graham_Wright]

We head to the US in a few weeks and are researching step up transformers.

Victron seem to be the fore runner , but their transformer won't convert the US 60HTZ to UK 50htz.
How much difference does this make?
We power mostly computers and a TV with our power, so I thought that they would both be ok with a 60htz supply?

Any thoughts?

Step up?

 

[Lon nan Gruagach]

We head to the US in a few weeks and are researching step up transformers.

Victron seem to be the fore runner , but their transformer won't convert the US 60HTZ to UK 50htz.
How much difference does this make?
We power mostly computers and a TV with our power, so I thought that they would both be ok with a 60htz supply?

Any thoughts?

First thing to do is have a good look at the manual for each bit of kit. Many portable 240V 50Hz items can plug direct i9nto 110V 60Hz these days, particularly phone chargers and laptop computers. Do be aware though that these will then take twice the current, your ring main might not be happy.
Next is the rest that wont like 110V. Almost everything that dosent have a motor wont mind 60Hz, these should be happy with a transformer.
That leaves the fridge and air con. Do you have an inverter that can cope, if so check if your battery charger has got power by either of the above and that it can cope with the load.
If there really isnt a solution so far then I would look to hire kit that can plug in locally.
Failing that then there are frequency converters available (to hire).

NOTE if you do solve this by adopting different solutions for different bits of kit then you will have at least 2 mains installations, this is a source of extra safety issues, but only if you cross connect stuff.

edit add: Graham, yes its step up, running UK kit from mercan leccy.

 

[savageseadog]

You could consider an inverter. Charge with US power, simultaneously invert to UK power.

 

[john_morris_uk]

I've always found 220 available at the power socket in US marinas I've visited. The USA plug is expensive, but prod around with an AC voltmeter until you find which two terminals have got the 220 volts across them. Be careful as both will be floating well above any 'neutral' (by 110 volts as it happens) I've never had a problem with double insulated kit on the boat. Frankly the immersion heater doesn't give a monkeys where the terminals are 'above neutral'. It just wants 220 across the heating element. As others have said, lots of kit will accept 50hz or 60hz. Read the labels that are on them.

 

[Saguday]

Go to Airlink Transformers link here who make an excellent range of fully encapsulated marine toroidal isolating transformers.

You need the BT3232 which is 120V in 240V out, £240 one-off:

BT3232 link

I had the opposite problem, our boat is American with 120V electrics so rather than rip it all out we put a couple of their BT3121 240:120V units in (the boat has 2 shore power supplies, don't ask). The Airlink units are great, completely quiet being toroidal there's no laminations to hum and unlike an active device like an invertor there's less to go wrong. Be aware the Victron units have a fan and they are not sealed, so won't withstand immersion. They are also 3x more expensive than an Airlink Transformer You'll need suitable breakers etc on the 120V side.

Don't worry about frequency differences, I fretted about this but in the end we've not found any issue even running the Cruisair 60 Hz aircon at 50 Hz.

 

[EugeneR]

+1 for Airlink and toroidal transformers - less noise. Could go toroidal auto-transformer as you have common ground - less weight.

 

[EugeneR]

Adding to above, some electrical equipment will not work at different frequency - microwaves often seem to have issues.

 

[Playtime]

There are 2 factors to consider - frequency and voltage. I have plagiarised the following from another Forum where the same problem is being discussed.

Frequency:

The US system operates at 60Hz; the UK and Europe at 50Hz.


Most resistance (heating) and electronic (TV's, computers, etc.) systems that run on AC don't care if the power is 50Hz or 60Hz. The name-plate will say. The place line frequency typically matters is on devices that include a motor (a fridge or hairdrier are common examples on a small boat). Electric motors are usually quite sensitive to frequency (Hz or "cycles"). Also, microwave ovens are often frequency sensitive. Of course none of this matters for 12-Volt systems, as these are DC.

Voltage:


The basic US voltage is 110V per phase. The UK/Europe system is 220 or 240V per phase. However, many installations in the US, including most marina systems provide 2 phases which will give a 220V across the phases.



If you look behind your US power service (at the breaker box) you will find two hots (a red and a black), one common (white), and one "safety ground" (green). The common and ground are not connected in the service panel; however, they should be at the same potential; in other words there should be no voltage between them. The safety ground insures that if someone shorts a hot lead to earth ground, it will trip the breaker. In the US, you can get 110V between either hot side and common and 220V across the 2 hot wires with each wire being 110V above earth..


In Europe there is no need for 110 volt service, so there is only one hot lead and it is at 220 Volts. My understanding is that this makes it possible to have the common and safety ground as the same wire. So, European supplies are 3 wire with a hot (brown) and neutral (blue) and a safety ground (green/yellow).


If a boat is set up for 220V in the US the shore power deck connection has three pins. Two are hot and one is common. The voltage between two hot sides (ie across the 2 phases) is 220V. The voltage between any hot pin and ground is 110.


There should be no problem getting the 220V to the boat. You will just need a US marina connection wired correctly for 220V input to a European deck plug. However, you will need to check all your earthing and safety trips as both line and neutral wires will actually be carrying 110V wrt earth.


I would recommend finding a knowledgeable boat electrical guy who can survey all your equipment and safety systems as this is not something you want to get wrong!

 

[JumbleDuck]

"The basic US voltage is 110V per phase. The UK/Europe system is 220 or 240V per phase. However, many installations in the US, including most marina systems provide 2 phases which will give a 220V across the phases."

Yes. Although most household appliances in the US are 110V single-phase, high power appliances like electric cookers and washing machines are usually 220V, which is available just about everywhere. As you rightly say, it does provide a potential shortcut to running a European boat there, as long as you are very sure about your wiring.

 

[Lon nan Gruagach]

There are 2 factors to consider - frequency and voltage. I have plagiarised the following from another Forum where the same problem is being discussed.

Frequency:

The US system operates at 60Hz; the UK and Europe at 50Hz.


Most resistance (heating) and electronic (TV's, computers, etc.) systems that run on AC don't care if the power is 50Hz or 60Hz. The name-plate will say. The place line frequency typically matters is on devices that include a motor (a fridge or hairdrier are common examples on a small boat). Electric motors are usually quite sensitive to frequency (Hz or "cycles"). Also, microwave ovens are often frequency sensitive. Of course none of this matters for 12-Volt systems, as these are DC.

Voltage:


The basic US voltage is 110V per phase. The UK/Europe system is 220 or 240V per phase. However, many installations in the US, including most marina systems provide 2 phases which will give a 220V across the phases.



If you look behind your US power service (at the breaker box) you will find two hots (a red and a black), one common (white), and one "safety ground" (green). The common and ground are not connected in the service panel; however, they should be at the same potential; in other words there should be no voltage between them. The safety ground insures that if someone shorts a hot lead to earth ground, it will trip the breaker. In the US, you can get 110V between either hot side and common and 220V across the 2 hot wires with each wire being 110V above earth..


In Europe there is no need for 110 volt service, so there is only one hot lead and it is at 220 Volts. My understanding is that this makes it possible to have the common and safety ground as the same wire. So, European supplies are 3 wire with a hot (brown) and neutral (blue) and a safety ground (green/yellow).


If a boat is set up for 220V in the US the shore power deck connection has three pins. Two are hot and one is common. The voltage between two hot sides (ie across the 2 phases) is 220V. The voltage between any hot pin and ground is 110.


There should be no problem getting the 220V to the boat. You will just need a US marina connection wired correctly for 220V input to a European deck plug. However, you will need to check all your earthing and safety trips as both line and neutral wires will actually be carrying 110V wrt earth.


I would recommend finding a knowledgeable boat electrical guy who can survey all your equipment and safety systems as this is not something you want to get wrong!

For phase, neutral, earth wiring (as in UK) a neutral to earth connection is considered a fault and will cause a RCCD to trip. The upshot of this is that there shouldnt be any need for the check (since a system that wont work would be considered to be faulty anyway). The neutral is, but is not necessarily near earth potential. As it happens the neutral is connected to earth at the power source (thats what makes a RCCD work), anywhere downstream of that is subject to volt-drop causing it to no longer be at earth potential.

 

[William_H]

In Europe there is no need for 110 volt service, so there is only one hot lead and it is at 220 Volts. My understanding is that this makes it possible to have the common and safety ground as the same wire. So, European supplies are 3 wire with a hot (brown) and neutral (blue) and a safety ground (green/yellow).

Now I don't know much about European systems but certainly in Australian 240v systems there is no 110v appearing any where. The system uses 3 phases each 240 to ground/neutral so any one of the 3 is used for domestic 240v supply. For high powered equipment, electric hot water for instance or large motors all 3 phases are used giving 440v from phase to phase. So if UK and European systems are similar don't be looking for 110 v anywhere. olewill

 

[Saguday]

Adding to above, some electrical equipment will not work at different frequency - microwaves often seem to have issues.

Well... that's what I thought, of all the stuff on board I had concerns about two items: the aircon and the microwave oven, both US, both 60Hz.

I've now run these on 50Hz so far without issue.

I guess it depends...

 

[Saguday]

Personally I'd be wary of relying on US electrics in small out of the way places and would much prefer to put as much isolation between me and the shore power as possible.

 

[EugeneR]

Well... that's what I thought, of all the stuff on board I had concerns about two items: the aircon and the microwave oven, both US, both 60Hz.

I've now run these on 50Hz so far without issue.

I guess it depends...

In my experience the microwave "works", except it does not heat effectively.

 

[KellysEye]

In the USVI's the marina rewired a 110v american plug to accept 220v.

 

[JohnGC]

For phase, neutral, earth wiring (as in UK) a neutral to earth connection is considered a fault and will cause a RCCD to trip. The upshot of this is that there shouldnt be any need for the check (since a system that wont work would be considered to be faulty anyway). The neutral is, but is not necessarily near earth potential. As it happens the neutral is connected to earth at the power source (thats what makes a RCCD work), anywhere downstream of that is subject to volt-drop causing it to no longer be at earth potential.

Surprisingly large currents can flow if you short the earth and neutral at a UK 3 pin socket (assuming there is no RCD). I've seen around 7 to 8A. The potential difference to drive that is generated by the current flowing in other parts of the neutral connection (which has resistance) back to the distribution point at which the earth and neutral are joined. The common point maybe the local substation or a distribution panel in a factory.

Regarding 50Hz/60Hz.
Anything which derives its timing from the mains cycle will be effected. European equipment will run for shorter times in the USA and visa versa. Certainly I have known microwave ovens and bread makers that use mains frequency as their timing source.

 

[Graham_Wright]

I haven't read all the responses but a site transformer from 230 to 110 should work in reverse unless frequency becomes a problem.

 

[Plevier]

I've always found 220 available at the power socket in US marinas I've visited. The USA plug is expensive, but prod around with an AC voltmeter until you find which two terminals have got the 220 volts across them. Be careful as both will be floating well above any 'neutral' (by 110 volts as it happens) I've never had a problem with double insulated kit on the boat. Frankly the immersion heater doesn't give a monkeys where the terminals are 'above neutral'. It just wants 220 across the heating element. As others have said, lots of kit will accept 50hz or 60hz. Read the labels that are on them.

There is a safety issue here.
A boat wired for a European single phase system with 230V phase voltage (i.e. voltage between live and neutral) will normally have single pole MCBs and may have a single pole RCD which in fault conditions only disconnect the live side of the mains. Even if you have a double pole RCD, in my experience they are not the most reliable items. If you're running between 2 phases to get 220V line voltage this means even after a trip, all of your neutral wiring may be at 110V, and indeed conduction through connected loads will put the live side wiring at 110V too.
To operate on 2 phases all of your trips and breakers should be double pole for safety, alternatively use a 1:1 isolating transformer which lets you make the supply effectively single ended.
If you're getting a transformer, it might as well be a 2:1 step up to run from the single 110V supply, as the OP originally requested.

As a side issue, do you actually get 220V? I would have expected it to be 208V - which might be low enough to worry some equipment designed for 230V.

 

[JumbleDuck]

As a side issue, do you actually get 220V? I would have expected it to be 208V - which might be low enough to worry some equipment designed for 230V.

US domestic supplies use a two-phase (or split-phase) system, so the two phases are 180^o out from each other and the line voltage is therefore twice the phase voltage. Although phase voltage in North America is now nominally 120V +/- 5%, I gather that in many places is is still effectively 110V, which is just out of spec. It's a bit like the European standard of 230V + 10%/-6%, which allows us to stay on 240V and those funny foreigners to stay on 220V.

In industrial use I think they sometimes have three-phase supplies and therefore 120/208 rather than 110/220.