How dangerous is reverse polarity

[brananka]

I am on a site in France (hand picked by carefree ) It is reverse polarity I had to buy an adaptor from the site for twenty euros ,the site manager tells me its safe alot of caravaners here havent checked .

the camaping and caravan club care free say I should of read page 33 of the brochure personally I did not think it was common especially as they have checked the site out ,I have the usual three pin socket and I now use my french plug into this adaptor (good job I have one).
opinions would be nice I am no electrician .

 

[Damian]

Reverse Polarity is a British phenomenon.
The British Standard for wiring, conventionally, is to have the Live (or Line) switched, so that when an appliance is switched off, the Line is interrupted so you dont get a shock if you touch the, for example,the conductor in a light bulb holder.
With caravans, BOTH the Live and Neutral conductors are switched, so even if you have reversed ploarity , you will not get a shock when an appliance is switched off.

AC power is, as the name suggests, Alternating Current, and as such it is constantly changing the Live and Neutral (50 times a second).

Most AC equipment does not care what way the conductors are connected , but some are sensitive.

 

[ChrisUK]

If you are using a device , say a kettle, its switch will probably only be in the live connection. So if the polarity is reversed it will be live even if it is switched off. Toasters can be particulay bad on this as people are tempted to use such as a knife to extract burn toast and have been killed as they did not unplug first. This is why all domestic devices now have a molded on 13 amp plug because we are not trusted to wire one up correctly.
The fixed installations e.g. the water heater I would hope are double pole switch so should be OK - but I don't know for sure.
Continental vans and home are generally double pole switched which is much safer.

 

[ValA.]

Many British caravanners first read about reverse polarity on forums such as these, some of them make up home-made adaptors to 'correct polarity, others do nothing to 'correct' it. There is some very dangerous advice in some places about this.
Surely the problem with electricity is not the 'polarity', either reverse or correct - it's doing stupid things like sticking a knife into a toaster. Don't touch the inner workings of anything electrical with anything, until it is unplugged. In the case of any piece of equipment in your caravan which is fixed into the van, rather than connected via an electric socket in the caravan, that means unplugged from the hook-up bollard itself. For everything else just unplug it from the socket before poking inside it with anything!
If you stick to this then everything in and around your caravan should be safe!

 

[ProfJohnL]

Hello Branka

Unless you have faulty appliances you will not notice any difference in the way they work when there on normal UK supplies or supplies with reversed polarity.

The risk arises if an appliance or the caravan wiring becomes faulty. There is an increased risk that you may receive an electric shock, however if you did receive a shock then the caravans Residual Current devise (RCD) will still operate and prevent any serious injury.

As it is relatively easy to check for reversed polarity (some caravans already have a lamp that glows when the polarity is reversed) and also not too expensive to get hold of a reversing adaptor and they are pretty simple to use, why take the chance?

I have to recommend the safest methods which is to always check the polarity of your incoming supply, and if it is reversed, then use you newly purchased adaptor to correct it.

 

[Lutz]

The others have explained the situation quite well, but as they also have indicated, appliances with Continental plugs can be connected either way round in Continental sockets and I've never heard of this proven to lead to higher rates of injury than encountered in the UK so long as you don't do something stupid like sticking a knife in a live toaster.

 

[ProfJohnL]

Hello Chris,
Sorry to have to pint this one out you but the majority of new kettles are now double pole switched. - however that said, unless you know for certain, its best to assume single pole switching, and even with doubel poles switching , its not an excuse to poke anything inside the electrical side of things.

 

[Gafferbill]

……..just to correct the Prof!

You cannot purchase a cheap reverse polarity adapter……it would be illegal to sell such a thing in this country as it would be wired in an illegal fashion.
You can purchase a correctly wired adapter and reverse the wires yourself if you are competent.
There is also available a much more expensive (£40 + installation) switch that can be fitted to your caravan.

A friendly word of caution to Val A on the subject of electrical safety…

To quote from a post in the General forum

Our two-ring electric hob which came from an Argos half price sale, and cost £14.99. We caravan in France, always have an electric hook-up, and use it outside under the sun canopy to do all our cooking. It keeps cooking smells out of the van, stops me getting overheated when I'm cooking, and also the lovely smells cause people to stop and chat.
Our second best-buy was a portable fridge, which we also keep outside - and which keeps all our drinks cold - there was never enough room in the caravan fridge for bottles as well as food!

This is a French habit and is fraught with danger when it rains.
I have been on a French campsite where the owner spent the morning trying to find the offending set-up that was causing the site supply to trip continually.

The cause…….. a six socket extension supplying various appliances under a sun canopy of a French caravan after a thunderstorm.
The rest of us on site went without electricity for most of the morning!
　

 

[ProfJohnL]

Hello Bill
Yes you are corect about the sale of reversed polsarity adaptors in the UK, but I understand that such devices are for sale abroad which is where you would most likley need one.

 

[Lutz]

I have never seen a reverse polarity adapter on sale on the Continent, either. There wouldn't be a demand or a need, except possibly for visitors from the UK.

 

[Guest]

I would have to make comment on gafferbills post?

It would be illegal to sell a reverse polarity adaptor in the uk, so you buy a normal one and adapt it yourself....if you are competent!!!

Surely turning a legal thing into something illegal would be the hight of incompetence?

 

[Gafferbill]

Gary….. this is the current position.

The UK custom for wiring electrical circuits is controlled by legally binding regulations.
These UK regulations stipulate the colour of the insulation of each wire and to which terminal it must be connected.
The continuity of UK wiring is maintained all the way back to the Power Station from the end use appliance.
British made caravans are wired conforming to these regulations.
Continental wiring of electrical circuits and the governing Country’s legislation does not stipulate to which terminal an electrician has to connect the blue and brown wires….it is his or her choice.
The green and yellow earth wire is connected to the same earth terminal under both systems.
Take your British caravan to the Continent and it can therefore be subjected to a British phenomenon called ‘reverse polarity’.

Some people bother about this ……others do not.
I personally do and have made up my own adapter lead to correct what for me is a safety issue!
　
Both the major UK caravan clubs recommend this practice ( See below)

Advice from Camping & Caravan Club…….
Do take a mains tester though, to check the mains polarity. If the tester shows reversed polarity, which is often the case in Europe, for safety sake you should not use the supply unless you have the means to change the supply back to normal polarity. This can be achieved with another adapter lead that needs to be made up by an electrician or other competent person.

Pdf help sheet from the Caravan Club………
http://www.caravanclub.co.uk/media/19098/Reversed%20Polarity%20complete.pdf

 

[Lutz]

Continental wiring of electrical circuits and the governing Country’s legislation does not stipulate to which terminal an electrician has to connect the blue and brown wires….it is his or her choice.

Perhaps one should qualify this statement. Because Continental plugs are reversible, there's no need to make sure that the blue and brown wires are connected in any special order. One cannot, therefore, blame the electrician for acting indifferently.
By the way, a fair proportion of low powered appliances aren't earthed, but have a flat 2-pin 'Euro' plug that can be used universally in all European sockets, and this is obviously reversible.

 

[xtrailman]

I would have to make comment on gafferbills post?

It would be illegal to sell a reverse polarity adaptor in the uk, so you buy a normal one and adapt it yourself....if you are competent!!!

Surely turning a legal thing into something illegal would be the hight of incompetence?

Its only changing two wires over, not rocket science

 

[MichaelE]

You can purchase a reverse polarity adapter which fits into the van and detects if you reverse polarity ,by moving the rocker switch the situation is corrected

 

[Gafferbill]

Just to make clear to Lutz and anyone else.......
I was attaching no blame to Continental Electricians who are following their custom and legislation concerning electrical wiring.

 

[Guest]

Come on guys? I said 'make comment'...I'm hardly the one to quote regulations at people, but legally
doing it would be deemed incompetent rater than as Bill said competent

 

[Lutz]

Perhaps one the electrical boffins can answer me this question:
If a visiting Continental caravan is hooked up to an an EHU in the UK and it has an appliance plugged in the 'wrong' way round and switched on, doesn't this affect the polarity of the whole site? If it does, will this ever be noticed?

 

[ProfJohnL]

Hello Lutz,
Do I detect a but of devils advocate here?

As I am sure you really know the supply is considered to flow from generator to user, and thus and change in polarity will only afect items down stream of the ppoint where the pollarity is changed. Thus a single appliacne in a caravan plugged in the wrong way round does not change the polarity of the whole site. - whether it endangers the whole or part of the site depends on what nefarius use the appliance user is putting it to

.

As to whether it would ever be noticed, that is only likely to come to light if a fault conditoins arrises and causes injury or damage or any of the sefety devises to operate.

 

[David_L]

I have made up a 16amp 4343 short lead with a reversable connector in the cable (about 2ft long), this has an indelable red line marked down the case.When connected correctly the mark lines up and when reversed they don't.This takes the hassle out of the whole problem.