changing from 110V to 240V

[NickiCrutchfield]

Hi,
Can anyone give me an idea of the size of job it would be to change a boat from 110V to 240V. Obviously any mains appliances would need to be changed or run off an invertor/transformer, but can I just change the plugs on the shore lead and the sockets in the boat or is it more complicated than that?
Any thoughts or suggestions welcomed.
Many thanks.
Nicki Crutchfield

 

[ShipsWoofy]

110 is safer hence its use on sites etc.

Would it be possible to use a site transformer in line on your shore lines?

Or are you fed up of sourcing 110v appliances.

 

[William_H]

Basically you simply change the sockets over. However for the same power 110 volt system requires twice the current to acheive the same wattage so you may find that the wiring is heavier than necessary (good) but fuses or circuit breakers are of a higher current rating than you really want. So you may need to change them. Ensure you have RCD protective device but o my knowledge the current rating should be OK. You might want to check that you have a suitable earth system for the mains but it may be just the same as UK requirements. It is probably easier to buy new appliances than try to work with a dropping transformer. (unless yu intend to return to 110V lands. good luck olewill

 

[GarethTS]

Hi, Suspect you have a boat in from the US? Anyway reasonably straightforward depending on the boat spec.
Fit a 110v step down transformer as used for power tools to power say the colorifier (boiler) and the hob and fridge.
Fit a ring main with RCD consumer unit and UK sockets as required for everything else.
Replace the battery charger/power unit with a 240v unit.
Replace Microwave?
Just replace shore side plug with appropriate European one on power lead (if twin inputs link).
The balance of what to replace is really based on what is fitted and the supply available which is often only around 16 amps in the UK, whereas US boats sometimes have twin inputs as they are all electric, so you may have to ration usage.
Bear in mind though that a 110v hob say rated at 10 amps will consume around half that at 240v I think (via transformer).
I suppose I should add in this age of beaurocracy, that the work probably requires an electrician to carry it out!!
Anyway hope this helps so have fun /forums/images/graemlins/smile.gif

 

[Elessar]

correct - although you can keep all the 110 stuff including the microwave and charger, just change your sockets to the UK type.

buy the transformer from Machine Mart

so the shorepower inlet goes to the tranformer, and your new sockets (via the new 240V RCD). The output of the transformer goes to everything else on the boat.

Simple!

Couple of points though:
The amp usage at 110V does not change, so if it's 10A at 110V its (approx) 5A at 240V. Watt=VoltsxAmps, and the watts do not change if you fit a transformer.

110V will kill you! It takes about 65 volts to kill you actually, but the 110V site transformers float in voltage terms, so if you touch one wire it you probably survive, touch two wires in each hand and you're still a goner! So yes the site transformer is a relatively safe solution but 110V is not. (cue the pedant award)

 

[NickiCrutchfield]

Thank you all very much. Glad that it all seems as straigh forward as I hoped it would be.
Regards,
Nicki

 

[Norman_E]

Quote "110V will kill you! It takes about 65 volts to kill you actually, but the 110V site transformers float in voltage terms, so if you touch one wire it you probably survive, touch two wires in each hand and you're still a goner! So yes the site transformer is a relatively safe solution but 110V is not. (cue the pedant award)"

As I understand it the US 110 volt system is designed so that there are effectively two live wires, each carrying a 55 volt potential to earth. As it is AC current each wire alternates between positive and negative potential in opposition to the other wire. Thus there is 110 volt potential between them. That is why if you short one live wire to earth through your body you are unlikely to be killed. I do not know if site transformers do the same thing or have a live at 110 volt potental, a neutral and an earth, which would be more dangerous.
I am however a bit skeptical about the claims to greater safety because it is the current flow that kills you in an electric shock, rather than the voltage. Electric shock victims may die because of the shock to the nervous system but are are often slowly killed because they are unable to let go of the souce of current and their internal organs are cooked. I have survived a 240 volt shock because I was able to let go of the live wires I had touched.

 

[Elessar]

That's correct - it floats so it's about 55V either side of earth as you say. Yes it's current that kills, but on average you need about 65V to get enough current. (current=voltage/resistance). Normally you will be earthed, so the voltage difference that matters is between the voltage you're (accidentaly) holding and earth. You have a resistance, when you touched the 240V there was some more resistance between the 240V and earth than just your body, your shoes maybe. Thus the current was low enough for you to survive. If your shoes were wet you might be dead. Usually the shock makes your muscles tighten so you cant let go. You were lucky!

 

[Bejasus]

If the boat is a US purchase, the remember it's not just the voltage you have to be concerned about, the Hz difference to some of the equipment, mainly motors like electric pumps, clocks etc. can be damaged over a period of time.