# Help with reverse polarity



## DJMotorhomer (Apr 15, 2010)

Hi All

Were are now in Spain on our big tour on the 2nd day and already hit a hurdle.....reverse polarity... We have hooked up and plug in tester is showing no earth - rev polarity. I have with me two rev polarity hook up adaptors 1 with a UK plug on and one with a spanish plug on. The site we are on their EHU bollards are the standard euro 3 pins as used in UK EHU so how do I connect my rev polarity adaptor to the EHU point and then into MH if the other ends have a normal plug on ???

Any help would be great

cheers

DJM


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## erneboy (Feb 8, 2007)

For my own part I never test and never think about it. I have never seen anyone other than the occasional Brit testing, Alan.


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## iconnor (Nov 27, 2007)

Can you not open up the blue plug and swap the wires round?


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## tonyt (May 25, 2005)

Your reversed polarisation cable should simply be a miniature of your normal hook up cable, same socket and plug - it simply becomes an extension of your hook up cable - at the bollard end.

If you have a reliable rcd in your mh, don't worry too much about the reversed lines, rather try to find a hook up that has an earth.

Only my opinion.


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## DJMotorhomer (Apr 15, 2010)

looks like i am going to have to

DJM


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## Rosbotham (May 4, 2008)

I wouldn't bother about the reverse polarity.

But the lack of earth....no amount of rewiring will overcome that. I'd be very wary...


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## erneboy (Feb 8, 2007)

As it's a slow day here is a numpty question for the electrical experts.

How can there be an earth on a two pin foreign plug? Go easy on me please, Alan.


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## tonyt (May 25, 2005)

erneboy said:


> As it's a slow day here is a numpty question for the electrical experts.
> 
> How can there be an earth on a two pin foreign plug? Go easy on me please, Alan.


Quite right Alan - well the first sentence is


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## bigcats30 (Aug 13, 2012)

I find it funny out of all the caravans/motorhomes built...only us Brits seem to worry about reverse Polarity.

(yet not a single person has been fried by it)


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## Rosbotham (May 4, 2008)

What kind do you mean Alan?



The first type, clearly not. The second type has an earth pin in the socket that mates to a female connection on the plug. Strictly the latter is called a 3 pin plug, but I doubt many people would refer to them as that in common parlance.

The plug on the end of my leads is like the second, indeed I've not come across a strict 2 pin plug in UK camping accessory shops. I've probably had a blessed existence, but the EHU bollards I've encountered have had an earth pin to make connection on three pins. And unlike the OP, they appear to have been connected to earth too....


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## tonyt (May 25, 2005)

bigcats30 said:


> I find it funny out of all the caravans/motorhomes built...only us Brits seem to worry about reverse Polarity.
> 
> (yet not a single person has been fried by it)


Because all Continental built motorhomes have double pole switches therefore reversed polarisation is not a concern.


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## bigcats30 (Aug 13, 2012)

tonyt said:


> bigcats30 said:
> 
> 
> > I find it funny out of all the caravans/motorhomes built...only us Brits seem to worry about reverse Polarity.
> ...


But thousands of Brits go on holiday every year in Caravans and motorhomes and never have a problem.....like I said not a single person has been fried because of it.


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## Bill_H (Feb 18, 2011)

erneboy said:


> As it's a slow day here is a numpty question for the electrical experts.
> 
> How can there be an earth on a two pin foreign plug? Go easy on me please, Alan.


All the foreign 2-pin plugs I've seen have the earth on the outside edge, as two flat copper contact pionts, and the coresponding 2-pin sockets have an earth in their 'rim', so in fact there are 3 contacts, live neutral and earth.

AC stands for alternating current, with the live and neutral swapping polarities 50 times a second, so 'reverse polatiry' is a bit of a misnomer as they are constantly swapping or 'reversing'


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## DJMotorhomer (Apr 15, 2010)

I changed the other end of my rev polarity lead from a UK plug to the female 3 pin plug and changed round live and neutral...plugged in and still the rev polarity signal came up ?????

I give up !!!

DJM


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## tonyt (May 25, 2005)

DJMotorhomer said:


> I changed the other end of my rev polarity lead from a UK plug to the female 3 pin plug and changed round live and neutral...plugged in and still the rev polarity signal came up ?????
> 
> I give up !!!
> 
> DJM


That suggests one of two things: a faulty tester or there was no reverse in the furst place. 

Don't worry about it.

Is the earth OK now?


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## DJMotorhomer (Apr 15, 2010)

Tester has always been fine but still shows no earth

Is there any danger if we leave it as it is as everything seems to be running fine ?

cheers

DJ


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## bigcats30 (Aug 13, 2012)

DJMotorhomer said:


> Tester has always been fine but still shows no earth
> 
> Is there any danger if we leave it as it is as everything seems to be running fine ?
> 
> ...


Nothing will happen at all if you do leave it..........hence why you never read of someone dying of reverse polarity...ever.

Does your 'test' button still work on your circuit breaker?


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## DJMotorhomer (Apr 15, 2010)

Yes is does....so I take it if it doesnt trip everything is ok ?

DJM


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## bigcats30 (Aug 13, 2012)

Yep.......you'll be fine


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## pippin (Nov 15, 2007)

If I were realy paranoid or an electrical purist I would install a temporary earth using a wire from the chassis of the van to a long copper stake bashed into the ground.

I would of course empty a bucket of salt water on the ground (or even pi55 on it) to improve conductivity, especially if the ground were dry and sandy.

I would then spend a couple of thousand quid on a fancy "earth-effectiveness" meter to ensure the resistance was low enough.
If it wasn't then more wire, stakes and more pi55 would be added until it became low enough.

In practice I would simply open (another) botle of wine!


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## Gary1944 (Feb 21, 2009)

Earlier in the year had the same problem on my friends outfit. Found after much messing around that my converter from UK type to continental was OK. So fault with the converter. The centre pole (earth) was slightly larger on his new adaptor, and this was causing the problem.

We were not particularly worried about it, but couldn't work out why the reverse adaptor gave the same fault on the tester!

Hope that helps, Gary.


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## 1302 (Apr 4, 2006)

We carry a reverse polarity tester and a connector lead that has the socket end connected the other way round. If it doesnt read right then we fit the 'arse about face' lead.

I was told (and believe) that reverse polarity 'can' feck up your telly/fluorescent lights/laptop...

...until someone tells me 100 percent that I am wasting my time (rather than the ramblngs of a few knowalls) then I will drag out my 'other' lead 

I hope the OP got sorted...


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## grizzlyj (Oct 14, 2008)

pippin said:


> If I were realy paranoid or an electrical purist I would install a temporary earth using a wire from the chassis of the van to a long copper stake bashed into the ground.


I used to do something like this until I read on MHF that if the campsite does indeed have a dodgy earth, your DIY set up "could" end up earthing the whole site, making your set up very dangerous indeed.

I bought a new tester with LEDs which shows an earth when the older tester does not.

I've also hooked up to a site EHU that shows an earth with a 25m lead in use, but no earth when the tester is directly in the EHU socket (no lead at all).

Just my ramblings though.


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## Rosbotham (May 4, 2008)

bigcats30 said:


> Nothing will happen at all if you do leave it..........hence why you never read of someone dying of reverse polarity...ever.


Reverse polarity and a lack of earth connection are two completely different issues. Agree that for reverse polarity, worst situation is internals of appliances are live when turned off (so ok as long as you don't take it apart or e.g. touch a bulb housing). Problem with earth fault is you don't know _what_ the earth is connected to. If nothing, it could be harmless other than your circuit breakers mightn't work - but if the earth isn't earthed you've no idea what it's connected to; e.g. it could be live for all you know. I'd rather have no earth than one that I don't know where it goes to...


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## Penquin (Oct 15, 2007)

One other little thing we have discovered in sunny (yes it is!  ) Spain, where we are at the present.....

if you are plugging in to a normal socket (not the blue international ones) you may well be able to solve the "reverse polarity" issue very easily by turning the plug upside down........

I have a reverse polarity wire set up and a tester and discovered this when we plugged into our relative's ourtside socket - very easy, very quick and the earth is connected properly too........

Worth checking if you do have to use the"2-pin" connecting round plug to link - the earth connects via BOTH sides so having it upsoide down does not cause problems - assuming that there is an earth there to start with of course...... :lol: :lol: 

It's worked for us!

Dave.


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## DJMotorhomer (Apr 15, 2010)

1302 said:


> We carry a reverse polarity tester and a connector lead that has the socket end connected the other way round. If it doesnt read right then we fit the 'arse about face' lead.
> 
> I was told (and believe) that reverse polarity 'can' feck up your telly/fluorescent lights/laptop...
> 
> ...


Hi

well we still show no earth and everything is ok including laptop I am on now 

Cheers

DJM


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## LaMB (Oct 20, 2011)

A simple thought:-

You can install a 2 pin plug either way up - so obviously there cannot be a problem with reverse polarity. I guess we Brits are a bit paranoid about electricity.


Remember its volts that jolt and mils that kills. Having checked mains voltage occasionally with my finger (and indeed shocks of higher voltage from capacitors), I'm still here!

However I don't recommend it and always keep one hand in your pocket!

A further strange thought is that electricity is transmitted over a four wire system of three phases and an earth, which would lead you to believe that the return/neutral/black/blue wire is earth anyway - or am I missing something?

Martin


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## tonyt (May 25, 2005)

Whether or not Reversed Polarity is a "danger" (and the debate continues......), - for anyone who has a worry about it and can't be doing with testers and reverse cables, why not just replace your single pole switch/sockets with double pole.

Around a 30 minute job and then forget you even heard the phrase.

Not expensive : Switch/socket

You can then recover the cost by putting your reverse cable on Ebay.

If you have a continental built MH it will probably already be fitted with double pole.

This does not address the "No Earth" situation.


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## Geriatricbackpacker (Aug 21, 2012)

We winter in India and with their electrical practices my worries about 'all matters electrical' suprisingly diminished when we are not there! 
I have never really understood the polarity issues and in my ignorance have always reverted to that age old practice of if it works great and if it doesn't wind up the EHU lead and chuck it back in the locker. We have only ever encountered this problem once and that was in the UK. 
Very interesting thread and although still non the wiser I do feel that I would have wasted a lot of time possibly worrying over nothing. Hopefully nobody out there is going to disillusion me... 8O


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## bigcats30 (Aug 13, 2012)

Geriatricbackpacker said:


> We winter in India and with their electrical practices my worries about 'all matters electrical' suprisingly diminished when we are not there!
> I have never really understood the polarity issues and in my ignorance have always reverted to that age old practice of if it works great and if it doesn't wind up the EHU lead and chuck it back in the locker. We have only ever encountered this problem once and that was in the UK.
> Very interesting thread and although still non the wiser I do feel that I would have wasted a lot of time possibly worrying over nothing. Hopefully nobody out there is going to disillusion me... 8O


You have nothing to worry about.......as I've said and keep on saying

No one has yet died from reverse polarity......So that's, over the years, MILLIONS of people who have been on holiday in Europe without an issue....yet we still go on about it.

But people don't like looking at the facts.


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## raynipper (Aug 4, 2008)

Yep, it's a scam brought on by Elf n Safety to justify their jobs.

OK Gerry, apart from you..... :roll: 

Ray.


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## oldun (Nov 10, 2005)

Here's my twopence worth.

Reversed polarity. Normally this will be covered by the RCD tripping but take care when making a repair. With reversed polarity the fuse will be in the line-out and not the line-in. This means that the electrical uniy will still be live after the fuse has blown. Switching off and unplugging should remove all possibilities of danger

Earth testing. The usual plug type tester is not very good at testing the earth as it uses only a minute current during test. This means that the result will be positive even if only a fine single strand of earth cable is connected.

However this type of tester is still valuable and much better than nothing but do bear in mind it;s limitations.

One further comment. Just because many people have been careless with safety and got way with it is not a recommendation for following this practice. It it is reasonably easy to make something safe why not do it and avoid the very small possibility of an accident?


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## oldun (Nov 10, 2005)

bigcats30 said:


> ....like I said not a single person has been fried because of it.


Can you offer facts to prove this ridiculous statement?


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## oldun (Nov 10, 2005)

DJMotorhomer said:


> 1302 said:
> 
> 
> > We carry a reverse polarity tester and a connector lead that has the socket end connected the other way round. If it doesnt read right then we fit the 'arse about face' lead.
> ...


Laptops, shavers, electric toothbrushes, cameras and many other devices are double insulated and do not need or use an earth.

Fridges, electric fires, mains distribution units DO need an earth. All regulatory authorities agree with this statement even if other forms of protection are present.

To use such an item unearthed is potentially very dangerous.

Obviously if no fault develops then an earth will not be needed but if a fault develops then an earth may be very important.

Its interesting hearing al manner of people, many completely ignorant to the dangers of electricity, telling us all that we can ignore all the safety regulations with impunity.

When your child or wife dies because of your ignorance please remember that you are 100% responsible


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## bigcats30 (Aug 13, 2012)

oldun said:


> bigcats30 said:
> 
> 
> > ....like I said not a single person has been fried because of it.
> ...


Can you offer facts that someone has whilst in their caravan/motorhome.

Again I'll say it.....MILLIONS of people go into Europe every year and we've not had 1 reported incident in any of the camping type mags etc

NOT 1.....even if there was 1 thats not even 0.1 percent

Why do people ignore THESE simple facts??


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## bigtwin (May 24, 2008)

oldun said:


> Here's my twopence worth.
> 
> Reversed polarity. Normally this will be covered by the RCD tripping but take care when making a repair.


Why would the RCD trip on 'reverse polarity'?


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## rayc (Jun 3, 2008)

bigtwin said:


> oldun said:
> 
> 
> > Here's my twopence worth.
> ...


I believe that he doesn't means that the RCD will trip if the polarity is reversed but that if there is a fault on the circuit the RCD would trip no matter what the polarity of the supply.


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## rayc (Jun 3, 2008)

I have 16th edition in electrical installation so hesitate to offer my point of view on an open forum. I have yet to experience any malfunction of equipment if the N & L are reversed. I worked in Saudi Arabia using both 220 and 110v circuits and equipment. Step Up and Step Down transformers were used all over the place to mate up equipment requirements to the supply voltages. There appeared no concern over polarity and I saw no injuries or equipment malfunctions as a result.

It is when you start to work on circuits that it can be important especially if when you believe you have isolated supplies you do not do a final voltage check before touching anything in the circuit. That's what the person in the example from a post on the web failed to do.

" i once connected a consumer unit wrong ,all the circuits were wired correctly and all worked but because the mains were wrong way round all the "neutrals" were now lives.
With the single pole switch off and all the fuses out i still had a live supply at the light i was working on , i found out the hard way as i completed the circuit to earth , that's reverse polarity"

It can do no harm at all if those people who believe reverse polarity is a problem or a hazard for them to use a properly constructed reversal lead. If it makes them feel safer then its right for them.

Personally I think one of the biggest dangers is stepping out of a caravan or MH in a thunderstorm. I know that is so because the son of a friend was struck by lightning and died as he got out of the caravan to have a pee in a hedge. He had no shoes on. It was in the Dordogne.


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## bigtwin (May 24, 2008)

rayc said:


> bigtwin said:
> 
> 
> > oldun said:
> ...


I was just a little bit surprised to see such a "ridiculous statement" :wink: amongst the remainder of such an authorative series of posts by oldun.


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## Rosbotham (May 4, 2008)

rayc said:


> I have 16th edition in electrical installation so hesitate to offer my point of view on an open forum. I have yet to experience any malfunction of equipment if the N & L are reversed. I worked in Saudi Arabia using both 220 and 110v circuits and equipment. Step Up and Step Down transformers were used all over the place to mate up equipment requirements to the supply voltages. There appeared no concern over polarity and I saw no injuries or equipment malfunctions as a result.
> 
> It is when you start to work on circuits that it can be important especially if when you believe you have isolated supplies you do not do a final voltage check before touching anything in the circuit. That's what the person in the example from a post on the web failed to do.


Agree totally Ray. Only thing I'd add is "work on circuits" in this context includes something as trivial as changing a light bulb...socket will still potentially be live when switch is turned off if it's only single pole.

What intrigues me though is when I had reverse polarity, the "on" light on my electric hob & oven glowed...faintly rather than properly. Haven't managed to come up with a decent explanation for that one.


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## oldun (Nov 10, 2005)

bigcats30 said:


> oldun said:
> 
> 
> > bigcats30 said:
> ...


I am not ignoring the facts that I have never seen any reported accident due to reversed polarity and I, like you, cannot see any real danger with it.

What I am querying is the fact that you state that throughout the whole wide world, across all the nations therein you know for an absolute fact that no one has ever been injured by an electri8c system suffering reversed polarity.

How have you managed to do such an investigation involving everyone in the world today?

Making such ridiculous statement only undermines the value of what you are saying.


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## bigcats30 (Aug 13, 2012)

oldun said:


> bigcats30 said:
> 
> 
> > oldun said:
> ...


I didn't say the whole wide world at all....in fact I quite clearly said in my statement that Millions of Brits go into Europe every year yet we've not heard of ONE incident of someone being killed (or injured for that matter) because of reverse polarity.

We all know that if someone did every caravan and motorhome mag would be over it like a tramp on chips.........not to mention the people who seem to think this is a issue for people traveling to Europe.

It's yet more hearsay rubbish (like gas attacks, nitrogen in your tyres, etc) that for some reason seems to spread like wild fire.

I guess people need to believe in rubbish rather than look at the facts.


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## joedenise (Jul 20, 2007)

If someone does get fried I would blame the whole of the British caravan and motorhome industry as we have been in Europe long enough now and they can't say they didn't expect anyone to visit Europe. they just do a cheap quick way out cover for them by fitting a reverse polarity indicator 

joe


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## rayc (Jun 3, 2008)

joedenise said:


> If someone does get fried I would blame the whole of the British caravan and motorhome industry as we have been in Europe long enough now and they can't say they didn't expect anyone to visit Europe. they just do a cheap quick way out cover for them by fitting a reverse polarity indicator
> 
> joe


UK manufacturers are members of the NCC. The NCC say "The NCC Product Approval Scheme imposes a strict inspection regime on manufacturers to provide consumer protection over and above the requirements of the British/European standards. Every unit that has been approved is licensed to carry an NCC Approved Badge. A certificate is also issued to the consumer detailing the specification of the model that was inspected and approved."

http://www.nationalcaravan.co.uk/downloads/Benefits_Approval.pdf

At the NEC I saw that motor homes and caravans manufactured by their members had a big green sticker with a tick and words to the effect that they meet all standards.
In comparison non NCC members merely got a red sticker with the words "Approved for use on UK roads".

The suggestion being that membership of the NCC leads to a better manufactured product and woe betide anyone buying one manufactured by johnny foreigner. :lol:


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## joedenise (Jul 20, 2007)

but does that excuse them ? i'm not sure it would especially now there are all electric caravans

joe


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