240v power in Caribbean.

[Allan]

Last night we tried to plug into marina power in St Lucia. The boat has a reverse polarity light which came on, on the Taplin electrical panel. I then fitted a polarity changer and the light came on again. When I checked with a meter, live to neutral is 240v, live to earth 120v, neutral to earth 120v. I assume this is something to do with the power being derived from a US 120v system.
Is this likely to do any damage to the standard boat electrical/electronic devices?
Allan

 

[blenkinsop]

My understanding when in the Caribean (specifically Trinidad) with this question was that the 220/240v was created by connecting two 110v supplies to one outlet. Might be ok for charging batteries via a smartcharger but not for using electric motors eg drills etc. Not an electrical expert, so leave it for someone else to come up with all the technical terms.

 

[jdc]

Last night we tried to plug into marina power in St Lucia. The boat has a reverse polarity light which came on, on the Taplin electrical panel. I then fitted a polarity changer and the light came on again. When I checked with a meter, live to neutral is 240v, live to earth 120v, neutral to earth 120v. I assume this is something to do with the power being derived from a US 120v system.
Is this likely to do any damage to the standard boat electrical/electronic devices?
Allan

So this wasn't Rodney Bay marina then, where we have absolutely no reverse polarity problems and all mains electricity is UK style, even 13A plugs.

However much of the Amaricas uses 3 phase 127V, which give 220V between phases. This is of course symmetrical Live - Earth and Neutral - Earth. But if you measure it carefully isn't 110V - 100V giving 220, but 127V - 127V giving 220V.

Whichever, I think it extrremely unlikely that it will in any way damage tools, toaster, battery charger or immersion heater. Almost all equipment is 'double insulated' these days, and actually has no connection at all to 'Earth'.

 

[superheat6k]

Fine to use, but first make sure you have no earth to neutral connections on any of your equipment - you should not have (false earth neutrals can be lethal), but a simple check with a meter first with shore power disconnected, otherwise you will short out one side of the supply to neutral via the onboard earth ink to neutral.

The only feasible onboard link to neutral will be at a generating source, so if you have a generator, which must not be connected when on shore power anyway, and possibly similar if you have an inverter. If you do have an inverter used to charge your batteries then I would find the earth neutral link within and break it whilst using this shore power and reinstate it before you use it in inverter mode again.