Generator/Reverse Polarity

Could well be because the generator produces a modified sine wave rather than a pure one, that the reverse polarity circuit is sensitive to this. I wouldn't bother about it.

If the polarity was reversed then the light would stay on so I am inclined to agree with the other posts that it could just be the nature of the waveform from the generator. A poor Earth could also cause a problem.

Thank you Metheven & hitchglitch for your replies.  Please can I ask is it ok to test the plug sockets in the MH with a socket tester?

 ...  Please can I ask is it ok to test the plug sockets in the MH with a socket tester?

Course you can, but don't beat yourself up over polarity. Just don't poke inside toasters/etc with a knife while it's plugged in. 😉

 If there is nobody close to you use it, or if there is, just ask if it is alright to use it. You will soon be told if it is an annoyance. You must have a reason as to you wanting to use a generator, don't be put off by others that don't know your reasons. .

Our Swift manual says that the RP light coming on may happen with some generators because (as I understand it) the live and neutral conductors are each approx 110V above Earth i.e. the Earth is connected to the centre of the windings which each generate 110V giving a total of 220V between them.

This is done so that the maximum voltage above Earth is 110V (safer)

The fitted RCD inside should be tested regularly and aims to prevent any risk of electric shock by assuming that any difference between current flowing in Live and Neutral conductors is going through a person therefore it shuts of the supply.

Therefore RP light on is not a big worry but...

If I were using a generator, I think I'd expect to find an Earth post on the generator and drive in a suitable metal stake (Id make it at least a foot long, or more?) to act as an Earth but of course, following the makers instructions (from the EU20i manual, there does appear to be an Earthing point on the control panel)

Always ready to hear other justified views.

Definitive answer?:

https://caravanchronicles.com/guides/understanding-generators/

The bit headed Update explains it well (IMHO)

Interesting article which raises some issues which I had never had a reason to think about as I have never owned or contemplated buying a generator. Clearly, without the EHU connected, the “earth” of the van or motorhome is floating, as is the neutral. If you plug in a generator you would expect the generator metal work to be used as an “earth” and connected to its neutral. The van Earth would be connected to the generator Earth through the Earth wire in the connected cable. If the generator doesn’t have the neutral connected to the earth then there is no return path to allow an RCD  to work  

All I can conclude from this is - read the generator manual carefully to find out how it’s connected and what is recommended. An Earth spike for the generator may be sensible and can’t do any harm.

As I mentioned earlier, a flickering reverse polarity light could indeed relate to earthing problems.

In my career I worked on many types of electrical systems; the USA and parts of Southern Europe can be quite different. The point being that it is difficult to give definitive advice without knowing quite a lot about the equipment you are dealing with.

I'm fairly sure that modern RCDs measure currents going in via Live and out via Neutral and if there's any difference over their design trip current (can be 30mA) they assume that difference is going through a person down to Earth and cut off the supply therefore no Earth actually needed?

Of course if you touch both Live and Neutral conductors then it won't trip so I'd not recommend that!

https://en.wikipedia.org/wiki/Residual-current_device