# Polarity tester. Do I need one?



## bofb (May 29, 2008)

Off to Paris and Brittany at the weekend (First time!). Is a polarity tester essential and if so where could I get one at short notice?


----------



## StAubyns (Jun 4, 2006)

I think so, and a local Maplins is a good bet.

I found 3 instances of reverse polarity in our recent French trip

Geoff


----------



## Melly (Jul 5, 2007)

I spent 6 weeks in France this year and most of them had reverse polarity.


----------



## Zebedee (Oct 3, 2007)

I'd certainly get one.

Most good accessory shops should have one, or the Port shop probably . . . perhaps???

I'm not bothered about reverse polarity (won't bore you with reasons here) but very occasionally you find an EHU post with no earth.

That does bother me - a lot, and the polarity tester will have this function included.

Have a good holiday.


----------



## bofb (May 29, 2008)

*What a great website!*

Thanks to all. Looks like I'm off to Maplins.(For a polarity tester, not a holiday!) This must be the most useful site I've ever subscribed to. Cheers.


----------



## Melly (Jul 5, 2007)

Make sure the one you buy is not a faulty one see this earlier post
http://www.motorhomefacts.com/ftopic-49439.html


----------



## safariboy (May 1, 2005)

If you are taking a polarity tester you also need a lead specially wired to restore the polarity to the correct way round.
A 16A plug connected to a 16A socket with the live and neutral changed over.
You cannot buy one of these and have to make it. The socket and plug earth (green/yellow) wire remains connected as usual.
The cable between the two must be the round stranded caravan/ motor home type. Available at any caravan store.
If you detect reverse polarity simply fit this between your van and the camp site bollard. (It does not matter which end).
All should now be well. If not I would not use the outlet as there will be some more fundamental problem.


----------



## wilse (Aug 10, 2007)

we've been to france 2 times, once for 2 weeks, and again for 6 weeks, and I've never used mine!

wilse


----------



## Grizzly (May 9, 2005)

wilse said:


> we've been to france 2 times, once for 2 weeks, and again for 6 weeks, and I've never used mine!
> wilse


The bigger, commercial sites tend not to have reversed polarity- though this is not always true- but smaller, municipal sites quite often do.

It's not confined to France and happens all over Europe so it is wise to check on every site, including aires.

G


----------



## tonyt (May 25, 2005)

Zebedee speaks wise words 

It's worth the fiver and a little effort to check that earthing. I wouldn't sleep well if I were plugged in with no/faulty earth.


----------



## safariboy (May 1, 2005)

The other point to watch with continental hook-ups is the available current. In this country it is normally 16A but in France etc. it can often be as little as 6A or less and will only run the fridge and battery charging. Kettles, water heaters etc. are a problem. You need to know the current used by each of your appliances.
It is sometimes possible to pay more for more current.
There are plenty of threads on the subject.

I hope that all goes well.
Enjoy


----------



## wilse (Aug 10, 2007)

also spent 7 weeks in Portugal, and 4 days in Spain (yuk) and never used it there either.


----------



## tonyt (May 25, 2005)

wilse said:


> also spent 7 weeks in Portugal, and 4 days in Spain (yuk) and never used it there either.


Are you saying you never had to use it or you never checked the power supply?


----------



## wilse (Aug 10, 2007)

I tried it on my first outing, then 8 months later when we did a 3 month-er I didn't bother...

At Biarritz, I met a chap, who said you could reverse the polarity (when using the two pin european plug) just by turning the plug 180 degrees and re-inserting it into supply?? is this correct??


wilse


----------



## Zebedee (Oct 3, 2007)

wilse said:


> At Biarritz, I met a chap, who said you could reverse the polarity (when using the two pin european plug) just by turning the plug 180 degrees and re-inserting it into supply?? is this correct??
> 
> wilse


Not if it has an earth connection - and I wouldn't go within a yard of it if it hadn't!!

Cheers


----------



## wilse (Aug 10, 2007)

Zebedee said:


> wilse said:
> 
> 
> > At Biarritz, I met a chap, who said you could reverse the polarity (when using the two pin european plug) just by turning the plug 180 degrees and re-inserting it into supply?? is this correct??
> ...


I thought the 'female' bit of the 2 pin european plugs had an 'earth' prong on either side? IF this is the case, would this not reverse the polarity on everything be AOK??

Just curious

W


----------



## Zebedee (Oct 3, 2007)

wilse said:


> I thought the 'female' bit of the 2 pin european plugs had an 'earth' prong on either side? IF this is the case, would this not reverse the polarity on everything be AOK??
> 
> Just curious
> 
> W


Hi Wilse,

On a good many of them yes, but there are a number of confusing variations as you travel through Europe.

There is a mixture of polarised (non reversible) and unpolarized (reversible) plugs in use. See  ::here:: 

_Sod's Law again - the link to the image for the French one does not work._

Cheers


----------



## safariboy (May 1, 2005)

There are two styles of continental plugs. French plugs have an earth pin in the socket and are not reversible. German sockets have the earth contact on the side and are reversible. The plugs on adapters bought in the UK seem to work on both systems.
Two pin continental plugs will go in either way round but they are not suitable for connecting a caravan which should be earthed. They are for "double insulated" or "all insulated" appliances only. 
There are variations for example in Italy but you seem to find them only in houses and not for EHU points.


----------



## Hovis (Mar 28, 2007)

Safariboy knows what he is talking about. Buy a polarity tester and make up a reversed lead- don't forget to mark it. We have been to France this year, we are off again in a week, The chances of connecting to "upside down" electric as we call it are 2 out of 3. Always check.
Hovis :wink:


----------



## tonyt (May 25, 2005)

Hovis said:


> Safariboy knows what he is talking about. Buy a polarity tester and make up a reversed lead- don't forget to mark it. We have been to France this year, we are off again in a week, The chances of connecting to "upside down" electric as we call it are 2 out of 3. Always check.
> Hovis :wink:


I agree but in my opinion, it's far more important to check the earthing so make sure your polarity tester also gives you a green light for earthing. We came across 6 sites in France last year that had no/faulty earth.


----------



## teemyob (Nov 22, 2005)

*PC*

Hello there,

YES you would be well advised to buy a Polarity Tester, a decent one like a Martindale. Expect to pay arond a tenner.

Why?

Well as one example, the PCB's on Dometic refrigeration products do not like reverse polarity and if used long term in this state can cause board failure. Expect to pay anything from £150 - £350 or the PCB alone.

Regards,
Trev.


----------



## Mandi (Jan 10, 2008)

I'm glad this has come up because I keep meaning to ask about this. 

We just got back from hols in Belguim Germany and France. We carry two two pin continental adapters, one wired with the blue and brown round the wrong way. On the first site we encountered reverse polarity I changed the adapter to the RP one and it made no difference. The tester we have has about five rows of lights all telling different things. I tried all the sockets on the same bollard and got all different results except the correct one. We were only staying one night and the sockets were earthed so we lived with. So what are the dangers of reverse polarity?

Cheers. 8O


----------



## chrisndeb (Feb 7, 2007)

Hi all you sparkies out there
We are off to spain soon, Ive made a reversed lead up by switching the wires but im no sparkie all this talk about earth two pin plugs not to be used???? help as I said I have made up a reversed wire 2 pin plug and I have a normal 2 pin plug is this correct, our main fuse box thing in the camper has a warning light to tell us of reversed polarity if this lights up I will use the made up lead?????? Thanks Chris


----------



## safariboy (May 1, 2005)

2 - pin plugs are not suitable for connecting to an EHU bollard.
You need a continental 3-pin (which is seen as two pins on the plug and one on the socket.)
If there is no pin on the socket it should be the German system where the earth is on a contact on the outside of the plug. These will go in either way round and so you do not need a reverse polarity lead.
If you make up your own polarity reversing lead make sure that the earth is correctly connected - Green/yellow covered wire to the same earth poin on both plug and socket.


----------



## chrisndeb (Feb 7, 2007)

Hi
When i say 2 pin plugs i mean the ones from a camping shop already made up with a 2 pin plug on 1 end and the blue connector that goes onto the EHU cable on the other.
Thanks
Chris


----------



## sallytrafic (Jan 17, 2006)

Zebedee said:


> I'd certainly get one.
> 
> Most good accessory shops should have one, or the Port shop probably . . . perhaps???
> 
> ...


I've just come across my first UK site with a missing EHU earth.

I was so surprised that I suspected my lead and my checker before I confirmed that the earth was missing.


----------



## safariboy (May 1, 2005)

hi,
I think that we are both talking about the same plugs. I have seen 2-pin only (No earth) cables being used in France and Spain. They are flat plugs not round.

Have a good trip.
Safariboy


----------



## bobandjane (Dec 29, 2007)

chrisndeb said:


> Hi
> When i say 2 pin plugs i mean the ones from a camping shop already made up with a 2 pin plug on 1 end and the blue connector that goes onto the EHU cable on the other.
> Thanks
> Chris


Hi Chris n Deb. We have a lead about 4' long with the plug and socket that you have on your electric hookup lead, and one end your reverse the live and neutral, so when you plug in and your Red light comes ON, that tells you to use your reverse polarity lead, we unplug the van end and plug it in there. So sometimes you may have a 2 pin euro adaptor, then your hookup lead, then you may need your reverse polarity lead.

Hope this helps. Bob.


----------



## Penquin (Oct 15, 2007)

We spend several weeks each year in France and have a polarity tester and a reversing lead - both have been used about one in 4 times. French use either our style EHU or a simple french style plug. So a continental adaptor may also be needed - similar but with different ends to put into you cable run at the EHU end. You can buy polarity testers easily, some electrical control units have a built in system for live/neutral but not earth. I feel earth is probably the most important!

The simple French style has two pins for live and neutral and often a hole for the pin that comes out of the EHU post - this goes into the hole and touches a metal strip to complete the earth, but there are only two pins on the plug. These are readily available in accessory shops.

There is lots of excellent advice in the answers above, most are saying the same thing, well worth following; total\cost of all adaptors (continental style - standard, reversing - standard and polarity tester) is probably less than £20. What do you value your life, or your wife's or kids lives if they are with you?

Take it and hope you don't need it but find you do = happiness,

not take it and find out the hard way by equipment failure or electrical shock = tragedy and bad memories for years.

Enjoy your holiday, but take care. The French system of wiring is very different to ours (no ring main + spurs there, it's all spurs back to the distribution board), But polarity is much less important to them due to the way they are wired. Their vans and the like do not have anything like our electrical items to run and they are much more casual about plugging multiple things into one outlet - this overloads the wiring frequently in our experience!


----------



## Lys520 (Mar 24, 2008)

Hi

Can anyone tell me what these things look like - description etc. I've just done a search on Ebay and quite frankly don't have a clue!!!  

Any advice on how you use them/test etc.

Sorry to seem so dim. The only thing I know about electricity is how to plug in the orange cable and that took me a few times to master!!!!

Off to France for the first time abroad in the van next week and think I need to get this covered. I do have a two pin adapter.

Also, how do you know if you're not earthed?

Cheers to anyone who can help.

Lisa


----------



## drumshade (Mar 14, 2008)

hi all been watching this post does anyone have picts of what the plugs look like as i am confused  thanks ken


----------



## tonyt (May 25, 2005)

drumshade said:


> hi all been watching this post does anyone have picts of what the plugs look like as i am confused  thanks ken


There was a post a couple of years ago that put names and applications to them all - no doubt someone will be along shortly with a full explanation.

Edit 5 minutes later:

Just found it:

http://www.motorhomefacts.com/ftopict-12231-electrical.html+connectors


----------



## Lys520 (Mar 24, 2008)

Any advice on the actual tester?


----------



## Grizzly (May 9, 2005)

Lys520 said:


> Can anyone tell me what these things look like -!


This is a polarity tester. There are instructions on it. Basically you plug it into a 240v socket in the van and the little lights light up in different combinations. You are told which combinations mean reversed polarity or no earth. Couldn't be simpler. It's about the size of a 13 amp plug and the lights are at the top and orange ( 3 of them). All three on and you are safe and need do nothing.

G


----------



## Lys520 (Mar 24, 2008)

Thanks Tony/Grizzly

So, basically its a case of plug your cables in and then test, right?

Is this the same thing

http://cgi.ebay.co.uk/Mains-Electri...12|39:1|66:2|65:12&_trksid=p3286.c0.m14.l1318

Lisa.


----------



## Grizzly (May 9, 2005)

Lys520 said:


> So, basically its a case of plug your cables in and then test, right?
> Is this the same thing
> .


Yes, and yes. Arrive at site, plug in EHU cable, see what the polarity tester looks like and go from there. The appearance of the tester varies a bit by make but all the ones I've seen have got 3 lights that light up and a key to tell you what each combination of lights means.

I always put the tester in the 13 amp socket before the electricity is hooked up but that is paranoia on my part. It's definately the first thing you do before making tea or putting on any 240 v appliance.

G


----------



## Grizzly (May 9, 2005)

Lisa...speaking as one who does not do the actual decision making as regards what to plug into the mains for each possible option, if I had to do it, then I would make myself a little chart and stick it inside the locker door.

I'd copy the instruction chart from the front of the polarity tester and then write beside it what I need to do in each case. I'd make sure that I ran it by members of MHF first.

I know otherwise I'd be up all night worrying that I'd not done the right thng.

Just a thought...!

G


----------



## Lys520 (Mar 24, 2008)

Thank G

I think I'm going to go with the "if something is not right, we won't use electricity" route.

I only use electricity for the very basics....fridge, hair straigheners  phone charger etc so we can live without it.

Can't see me getting into reverse wiring stuff 8O 

Cheers

Lisa


----------



## Lys520 (Mar 24, 2008)

Just one last question (I promise).....

Can someone tell me in resonably simplistic terms, what no earth would actually mean?

Cheers

Lisa


----------



## safariboy (May 1, 2005)

You do not usually find "No Earth". The earth wire is a protection against a wire chaffing against the body of your motor home and making it live. This is unusual but could happen.
Otherwise it does not actually do anything.

The polarity problem is easy to deal with of you have a 16A plug and a 16A socket joined together with about 50cm of flexible cable. (Preferably the orange type) The live on the plug goes to the neutral on the socket and vice versa. It should have a clear label.
At the site plug in the van and the polarity tester. If the polarity tester shows "polarity reversed" add the change over link to your EHU cable and all should be OK.
If there is any other fault use a different pitch. (very often it will be a bollard fault not a site fault)
You cannot deal with any of the other fault combinations that the polarity tester can show. I have only ever once met anything else in a long time caravanning etc.

Polarity reversal on continental sites is very common and if you just do not use electricity when you find it you will only have electricity on a very few days.


----------



## chrisndeb (Feb 7, 2007)

Penquin said:


> The simple French style has two pins for live and neutral and often a hole for the pin that comes out of the EHU post - this goes into the hole and touches a metal strip to complete the earth, but there are only two pins on the plug. These are readily available in accessory shops.
> 
> Thats the lead we have. I have 2 of them 1 standard 1 ive switched the live and neutral and marked the lead in case its reversed (and our light will tell us). So thats were im getting confused the earth is on the EHU pole which goes into my 2 pin adapter. YES THINK ive got it, just got to hope the site (Spainish) have a earth pin on the EHU pole. THANKS
> Chris


----------



## safariboy (May 1, 2005)

Basically I think that you have got it sorted but you will meet 16A sockets (like the standard UK ones) with polarity reversed.
That is why I use a reversing link rather than have a 16A to continental plug adaptor with polarity reversed. 

Have a good holiday.

.Safariboy


----------

