Polarity Tester/Reverser

[Old Git]

Quite agree Steve.

 

I do have a polarity tester and reversing lead - in spite of thinking there's very little to worry about. Dave makes a good point however about a combination of rare events combining to create a problem.

 

Here we go again - another niggling little worry takes root, and will no doubt flourish. He's quite right of course, but it's knowing where sensibly to draw the line in some cases!

 

Where to buy the reminder cards - give it time!! My truck came with a reminder list stuck on the window of the driver's door. I read it thoroughly every time I enter or leave the cab.

 

Cheers

 

Dave

[twooks]

or - - just try the next plug-in - chances are that it will be ok

 

B-)

[Clive]

I believe you only need to be sure about good earth continuity.

Anybody been to Norway? They have three sets of mains wiring!

 

That.l confuse you!!!

 

Want more?

 

 

[eddie123]

I am off to France next week and purchased a plug in polarity tester yesterday. The shop assistant said that I could simply turn the French style two pin plug upside down to reverse polarity if necessary. I was sceptical about this any comments anyone.

[johnsandywhite]

Clive - 2007-09-02 11:58 AM

 

I believe you only need to be sure about good earth continuity.

 

:-D CORRECT. Unless of course there isn't an Earth fitted to the power point you are connecting to. Been there. (lol)

[crinklystarfish]

Clive - 2007-09-02 11:58 AM I believe you only need to be sure about good earth continuity. Anybody been to Norway? They have three sets of mains wiring! That.l confuse you!!! Want more?

Clive, been to Norway, stuck with the 12V only philosophy and consequently, as usual, had no hassle. I am though baffled by their floaty neutral / earth type weirdness. If you could explain it, in a way that real thickies would get, I'd like to understand.

[Old Git]

eddie123 - 2007-09-02 12:03 PM

 

I am off to France next week and purchased a plug in polarity tester yesterday. The shop assistant said that I could simply turn the French style two pin plug upside down to reverse polarity if necessary. I was sceptical about this any comments anyone.

 

Not so! You could if it is only a two pin plug on a fully insulated appliance and you do the upside down bit inside your (continentally wired) van, but what's the point as the rest of the van is still "reverse-polarised".

 

A continental hook-up plug has two pins and an earth socket in a triangular formation. (Sounds complicated when described, but simple in practice.) The socket on the supply post is reversed of course, and has two sockets and almost certainly a corresponding pin (which is the earth) - clearly visible if you look. If it hasn't got the pin I'd be very wary about hooking up, as you will not have an earth connection.

 

Your best bet if you are worried is to buy a short lead adapter to connect between your "UK" plug and the French sockets, and wire one end "back to front" - this has already been suggested earlier I think.

 

Just to further confuse (sorry) some continental electric supply points take only the continental plug, a few take only the "UK" plug, and others still offer the option of using either.

 

Regards

 

Dave

 

P.S. Edited to make the explanation clearer - not sure I have succeeded. Help please Clive.

[Clive]

Norway

 

This was covered in a recent copy of MMM so I guess its OK to post it here now.

What I would advise is that anybody who has a motorhome WITHOUT an un-ballance type circuit breaker should seriously consider getting one fitted.

Also be very wary of hookups that have no earth connection.

Even if the local sub station does not have an earth connection somebody else running from the same sub-station may have a fault that effectively provides an earth connection to the supply. If you happen to have another earth fault in your motorhome to a different point in the supply then the potential for electric shock and possible death exists. An unballance type earth leakage circuit breaker will still switch off the supply after the leakage current starts to flow.

 

NORWEGIAN ELECTRICITY.

These words are the response to a question from a Motorhome owner who was visiting Norway and found that his polarity and earth monitor test unit reported “peculiarly”.

 

Norway are in a state of flux regarding domestic mains distribution at the moment.

In most places the local sub-station transformer is connected in DELTA configuration providing 230 volts between phases. (Fig 1) A house (or a motorhome hookup) would therefore be connected between two phases. This is a fully isolated supply arrangement with no neutral and nothing at the sub-station transformer connected to earth other than the casing of the equipment.

 

In some places in Norway they have the transformers connected in STAR configuration. . But unlike the UK the transformer provides 230 volts between phases and about 133 volts between any phase and neutral. (Fig 2) The STAR point or NEUTRAL is connected to earth at the transformer. In this instance a house (or a motorhome hookup) would therefore be connected between the two phases to get a 230 volt supply.

 

However Norway are moving towards adopting the same system as us in mainland

Europe and the UK with it being the standard arrangement for new housing and Industry. Star connected sub-station transformers with the star point (Neutral) being connected to earth at the sub station. And each phase providing 230 volts between it and neutral and some 400 volts between phases.

 

In all three cases the transformers are three phase and the three phase outputs are 120 degrees apart electrically.

 

So the burning question is “Are you safe from electric shock”

 

Providing your motorhome is fitted with an unbalance type circuit breaker, that is one that compares the current flowing in the two incoming conductors (L & N) and opens if they are not equal, then I believe the answer is yes.

 

If the incoming supply is totally isolated and you have a frame fault on some equipment in your motorhome then as there is no path for any fault current to flow then none will and you will not get a shock. A bit like running from a portable generator! If however an earth fault at the sub-station or even at a neighbours house is present then should you then have a frame fault in your motorhome then an earth current will flow via earth between the two fault locations and cause your isolator to open removing the supply.

 

If the incoming supply is not totally isolated (2 or 3) and you have a frame fault on some equipment in your motorhome then as there is a path for a fault current to flow then some will and this will unbalance that flowing through your isolator which will open and remove the supply.

 

The individual line circuit breakers continue to provide overload protection irrespective of the type of supply.

Thanks to the Norwegian Electricity Industry Association (EBL) who provided the technical background information for this one!

C.Mott-Gotobed. G4ODM January 2007

 

[eddie123]

Dave. Thanks for reply. I don't wish to hijack the thread but my next point is relevant and may help others. The two pin French connector I purchased had earth points at 12 o'clock as well as at 6 o'clock (pins at 9 and 3 o'clock) so it does seem reasonable to simply turn the two pin plug upside down to correct reverse polarity if indicated whilst still retaing an earth. This would be at the site power point not inside the MH.

 

regards

Ed

[Old Git]

Thanks for this Ed. You learn something new every day. I've never seen one of those, or maybe I haven't been looking for one so didn't notice.

 

Sounds like a very good idea to me, and I'm sure it will be of general interest - wish I'd thought of it.

 

Regards

 

Dave

[twooks]

eddie123 - 2007-09-02 12:03 PM

 

I am off to France next week and purchased a plug in polarity tester yesterday. The shop assistant said that I could simply turn the French style two pin plug upside down to reverse polarity if necessary. I was sceptical about this any comments anyone.

 

no can do, although there are two pins there is also a hole [for earth pin????] to match the pin on the site side.

 

B-)

[Old Git]

eddie123 - 2007-09-02 2:50 PM

 

The two pin French connector I purchased had earth points at 12 o'clock as well as at 6 o'clock (pins at 9 and 3 o'clock) so it does seem reasonable to simply turn the two pin plug upside down to correct reverse polarity if indicated whilst still retaing an earth.

 

I think you are making the same mistake I did Twooks.

 

This sounds like a fancy new plug with two holes for the earth pin, which would allow you to turn it upside down. New to me too!

 

Never mind - this (below) was very quick and easy, and you might find it amusing.

[Ralph]

A bit of confusion here.

 

French plugs are of the type described by Eddie and on older French campsites you will need a converter to plug your standard cable into sockets designed to take them. And yes, you can reverse them just by turning upside down. I've also seen them in Switzerland and I assume other countries have them as well.

 

More and more French sites now use the standard 3 pin connecter that we have on our UK sites which, of course, aren't revesable.

 

Personally I never bother but just plug in. 8-)

 

[Old Git]

Thanks Ralph - confusion indeed.

 

I understand what Eddie is describing, but the "French" plug on my converter definitely cannot be turned upside down as it has only one earth socket. Eddie's plug will be OK because one of his dual earth sockets will be in position to receive the earth pin (in the socket) whichever way up he inserts it.

 

It's just that I have never noticed a plug with that configuration - probably because I haven't been looking, as I mentioned before.

 

Something new every day - thanks goodness!

[twooks]

the turn round option has been available in Germany and Switzerland for a while, not like the French to rush for rationalisation tho is it :D :D :D

not about to buy a new plug tho [tight - moi !! :D ]

still think the easiest option is to use another point.

 

B-)

 

 

ps ciao -

[Old Git]

Twooks

 

You haven't been rude (rude - vous!!) >:-) or complimentary :-D about my tinkering with your avatar (above). Could you be the most diplomatic person on the forum - or haven't you noticed yet.

 

Regards

 

Dave

[twooks]

oh Dave, I'm not rude - well not often - but then nor am I that observant, mind you you haven't done much to it - now - if you had it rolling around drunk - that I may have spotted :D :D :D :D

 

Anyway, this time I'm really OFF - away - not to be back for a couple of weeks - just in time for the York show and Food Fair with luck.

 

I blame GJH - it's these smoggies teaching everybody their bad habits - not that they should be held responsible for their actions - they just can't help it

:D :D :D :D :D :D :D

[hi graham :-> :-> :-> :-> :-> :-> ]

 

B-)

 

ps shall have an Amstel Gold to your health - sometime tomorrow

 

pps and the next day

 

 

ppps and the one after that

>:-) >:-) >:-) >:-) >:-) >:-)

[Old Git]

If rolling around drunk is what you would like fair maiden, you have only to ask :-D :-D

 

Have a good trip, or if you have really gone - hope you HAD a good trip.

 

Cheers

 

Dave

[Brian Kirby]

twooks - 2007-09-03 10:43 AM the turn round option has been available in Germany and Switzerland for a while, not like the French to rush for rationalisation tho is it :D :D :D not about to buy a new plug tho [tight - moi !! :D ] still think the easiest option is to use another point. B-) ps ciao -

But the earth connection is different in Switzerland, Germany, and I think, Austria to the French (Spanish and, if I remember, Portugese) version! 

The German socket has two wiping contacts at its edge in positions 12 and 6, with the two female connectors at position 3 and 9.  The French model has one male earth pin at 12, nothing at 6, and the two female connectors at 3 and 9. 

The German plug can be inverted to reverse polarity, with  the earth connection maintained, the French cannot. 

The reversible plug described is probably a "universal" model, and will also have a flat section adjacent the the two male pins, with a stepped keyway formed into it, that is required for (I think) Italy and possibly Spain.  This will have two French style female earth connections at 12 and 6, in addition to the adjacent German type wiping contacts.  So far as I know, these cater for nearly all mainland European eventualities except, probably, Norway.

[Old Git]

Thanks for this Brian. Very clearly explained, and so much easier to reply now I can use the proper terminology. (No pun here - I promise.)

 

According to your socket descriptions, my plug will only fit the French socket but why does it have an extra (redundant in this case?) wiping contact at 6. For convenience I'll repeat the photo of it that I posted earlier so you can clearly see its construction.

 

Thanks. No problem - just curious.

 

Off for a couple of days so may not reply - not being rude though!

 

Regards

 

Dave

[mikey72]

Hi,

 

the picture shows a CEE7/7 hybrid, the two wiping earths will mate with a german socket earth, the hole will mate with the pin in a France, Belgium, Poland, Czech Republic, Slovakia style socket.

Polarity can be reversed with the german style sockets, but not the others.

Mike

 

[Thai Bry]

Hi All

Anyone seen the latest MMM, as there are a couple of reverse polarity devices being reviewed.I currently have a 3 pin(UK style) plug which lights up three red lights if all is perfect.

I then have 2 x 2 pin connector cables, of which one is reversed, and I then also have a reversed polrity short cable connector - like the ones we use in the Uk, as I've been on certain German sites who use this type of connector, only to find it has reverse polarity.

So I can get rid of these extra cables and just have the "Auto Switch over" version that's being reviewed.

Opinions from any experts out there would be most welcome.

Thai

[Ralph]

I fully understand why earth / live reversed etc. would be dangerous but still can't see why people are so worried about live / neutral reversal.

 

Firstly the sockets in my (French) van have no switches.

Secondly the devices I plug in are mostly made in the far east for world markets, not just UK.

Thirdly, we don't seem to have stories of "Johnny Foreigner" being electrocuted on camp sites or in their homes.

 

So isn't it just sensible to Remove The Plug when not actually using any mains electrical device, or at least before putting one's grubby mitts inside?

 

My daughter used to live in France and, out of interest, I plugged my polarity tester into all her sockets. About 33% were reversed but they seemed to survive it.

 

 

 

[michele]

You know me probably way off track here once you have all had a good roll on the floor at the silly women you can then tell me to go back to sleep ;-)

 

Ours reverses itself inside the van so no problems 8-) i thought all vans were built like this in our day 8-)

[Thai Bry]

Ralph

Good point.

On one German site recently, when reversed polarity was found, I just plugged in the correction cable & all was alright.

I was told that the site recently had a CC member who said that reverse polarity was no big thing. I suppose it's because I'm not that technical with electrical stuff, that I get worried something might go wrong & so take the safe option.

Thai