Polarity

[Charles_374240409]

I am travelling to France in a couple of weeks, and I've bought my continental two pin adapter for the hook-up cable. I asked the lady in the shop if that was all I needed and she said something about making sure the polarity was correct. What would she be referring to and how can I check?

Charles

 

[BeemerMal]

Charles...the following may help:

ELECTRICAL SAFETY - Reversed Polarity Mains Lead

It is essential to ALWAYS check polarity, particularly when touring outside the UK.

In most European countries the live current flows in either direction and the mains switches control both the live and the neutral cables. This is known as REVERSED POLARITY.

However, In the UK live current flows in one direction and the main switches control only the single live cable.

This means when connecting to a European hook-up pillar, power can reach your appliances even if your caravan mains switch is off.

You could be in for a shock if it is not correctly wired up!

To be on the safe side you need the following:

1. UK 3 pin Polarity tester (available from caravan dealers)

2. Round 3 pin plug (blue) with a short cable attached to a standard 3 pin weatherproof socket at the other end.

3. Reverve polarity cable (where neutral and live are reversed) Make this up with a short length of cable and clearly mark the cable so it can easily be identified. The caravan Club Technical Department will send out a fact sheet if you need advise on how to make this up.

4. Not essential but I also made up a round 3 pin socket (blue) with a short cable attached to a standard uk 3 pin weatherproof plug at the other end. Usefull at home if testing mains on the driveway.

How to Check Site Polarity - UK & European Sites

Before making any direct connection to the caravan you MUST test

the polarity by carrying out the following simple checks:

Depending on the type of hook up the site has you need to plug in the correct plug that matches the bollard. Then plug the short cable that has the round (blue) 3 pin plug attached to the standard uk socket. Finally plug in the tester to check the polarity.

If the tester shows ALL CORRECT (all lights on) it meets UK spec and you can fit a standard UK mains lead to connect from the site hook-up pillar directly to the caravan inlet point.

If the tester shows LIVE & NEUTRAL REVERSED (left light on) it

means the site mains have reversed polarity. To make your appliances safe fit the reversed polarity lead to the site hook-up pillar and then fit your own UK mains lead to to the other end of the reversed polarity lead and connect this to the caravan inlet point.

If other lights on the tester are lit (eg,possible fault)

seek advise from site Management before connecting.

hope this helps....Mal

 

[Charles_374240409]

Charles...the following may help:

ELECTRICAL SAFETY - Reversed Polarity Mains Lead

It is essential to ALWAYS check polarity, particularly when touring outside the UK.

In most European countries the live current flows in either direction and the mains switches control both the live and the neutral cables. This is known as REVERSED POLARITY.

However, In the UK live current flows in one direction and the main switches control only the single live cable.

This means when connecting to a European hook-up pillar, power can reach your appliances even if your caravan mains switch is off.

You could be in for a shock if it is not correctly wired up!

To be on the safe side you need the following:

1. UK 3 pin Polarity tester (available from caravan dealers)

2. Round 3 pin plug (blue) with a short cable attached to a standard 3 pin weatherproof socket at the other end.

3. Reverve polarity cable (where neutral and live are reversed) Make this up with a short length of cable and clearly mark the cable so it can easily be identified. The caravan Club Technical Department will send out a fact sheet if you need advise on how to make this up.

4. Not essential but I also made up a round 3 pin socket (blue) with a short cable attached to a standard uk 3 pin weatherproof plug at the other end. Usefull at home if testing mains on the driveway.

How to Check Site Polarity - UK & European Sites

Before making any direct connection to the caravan you MUST test

the polarity by carrying out the following simple checks:

Depending on the type of hook up the site has you need to plug in the correct plug that matches the bollard. Then plug the short cable that has the round (blue) 3 pin plug attached to the standard uk socket. Finally plug in the tester to check the polarity.

If the tester shows ALL CORRECT (all lights on) it meets UK spec and you can fit a standard UK mains lead to connect from the site hook-up pillar directly to the caravan inlet point.

If the tester shows LIVE & NEUTRAL REVERSED (left light on) it

means the site mains have reversed polarity. To make your appliances safe fit the reversed polarity lead to the site hook-up pillar and then fit your own UK mains lead to to the other end of the reversed polarity lead and connect this to the caravan inlet point.

If other lights on the tester are lit (eg,possible fault)

seek advise from site Management before connecting.

hope this helps....Mal

Many thanks, Mal

Charles

 

[maurice_374247323]

Charles...the following may help:

ELECTRICAL SAFETY - Reversed Polarity Mains Lead

It is essential to ALWAYS check polarity, particularly when touring outside the UK.

In most European countries the live current flows in either direction and the mains switches control both the live and the neutral cables. This is known as REVERSED POLARITY.

However, In the UK live current flows in one direction and the main switches control only the single live cable.

This means when connecting to a European hook-up pillar, power can reach your appliances even if your caravan mains switch is off.

You could be in for a shock if it is not correctly wired up!

To be on the safe side you need the following:

1. UK 3 pin Polarity tester (available from caravan dealers)

2. Round 3 pin plug (blue) with a short cable attached to a standard 3 pin weatherproof socket at the other end.

3. Reverve polarity cable (where neutral and live are reversed) Make this up with a short length of cable and clearly mark the cable so it can easily be identified. The caravan Club Technical Department will send out a fact sheet if you need advise on how to make this up.

4. Not essential but I also made up a round 3 pin socket (blue) with a short cable attached to a standard uk 3 pin weatherproof plug at the other end. Usefull at home if testing mains on the driveway.

How to Check Site Polarity - UK & European Sites

Before making any direct connection to the caravan you MUST test

the polarity by carrying out the following simple checks:

Depending on the type of hook up the site has you need to plug in the correct plug that matches the bollard. Then plug the short cable that has the round (blue) 3 pin plug attached to the standard uk socket. Finally plug in the tester to check the polarity.

If the tester shows ALL CORRECT (all lights on) it meets UK spec and you can fit a standard UK mains lead to connect from the site hook-up pillar directly to the caravan inlet point.

If the tester shows LIVE & NEUTRAL REVERSED (left light on) it

means the site mains have reversed polarity. To make your appliances safe fit the reversed polarity lead to the site hook-up pillar and then fit your own UK mains lead to to the other end of the reversed polarity lead and connect this to the caravan inlet point.

If other lights on the tester are lit (eg,possible fault)

seek advise from site Management before connecting.

hope this helps....Mal

This quite the quaintest explaination of continental wiring I have ever seen . . .

Current flows the same in Europe as it does in Britain. The difference is in the way that the circuit is switched.

European (but not British) mains switches, when off interrupt both live and neutral - whereas British only interrupt the live.

In Britain the live connector is always live, and neutral is always neutral.

I Europe, because both live and neutral are switched, there is no need to ensure live and neutral are configured correctly (ac appliances work either way).

Normally this isn't a problem, and under normal circumstances you wouldn't notice any difference as the switch only needs to interrupt either live or neutral to turn an appilance off.

Problems arise however if you have a fault, as the fuse and any leakage detectors only monitor the live side of the circuit - and therefore will not provide protection to you, or your family.

 

[BeemerMal]

Maurice....My "quaint" explanation came straight from a back issue of Practical Caravan. It has served me well whilst touring in Europe.

Your last paragraph is by far the most important point with regard to electrical safety....this is, after all the reason why the polarity needs to be checked when touring abroad! And from my experience many caravanners do not check polarity at all.

 

[Robert_374242026]

We were on our way to Albufeira via Bilbao, stopped at a recomended site for enroute, we were only ones there to start with so checked polarity and it was "in reverse" ,no problem so put other adapter on ,still the same!!!,site manager notthere at the time but one of the garden staff said "no problem",by the way this is in Portugal,.Took my meter to the hitch up point , no earth , this is getting weird so went on gas .Awhile later a English motorhome pulled up and they connected up and appeared to be settling in so i went accross and asked did he check polarity,a puzzled look came on his face so I told him and checked his pointand found that same as mine.I warned him of the ossible danger, he thanked me and said he has never had any problems before. When i finally got the owner he said lots of UK come there and i was the only one to state this.We stayed on gas overnight!.

 

[rob_jax]

Polarity isn't an operational issue - AC appliances don't care.

And it isn't a safety issue with European made caravans or homes either - because they switch both the live and the neutral wires in MCB and RCD circuit breakers.

But it is a possible safety issue with UK caravans in Europe and your UK house, because the UK uses the cheaper (by a few pence) single switch on the live wire - and you may want to go around your house and check that the polarity is correct at each socket too.

Robert

 

[Ivan_5064847]

Hi Charles,

I bought two adaptors, one which I left as it was and the other I reversed the brown Live and blue neutral. I then taped some red electricians tape around the lead so that I could easily identify between the two.

Now when we arrive on site I plug the normal one in first, making sure that I am not running any 240v appliances, plug the socket tester into a socket. If the polarity is reversed it will be easily identified on the tester, just simply change your adaptor over and bingo. This saves lots of wiring time on site.

Regards

Ivan

 

[Charles_374240409]

Many thanks to all who replied.

I'm really looking forward to the trip.

Charles

 

[George2]

Hi,

I'm of to France shortly too, but all this talk of 'reverse polarity' seems like nonsense to me. Unlike the description above, AC electricity flows in BOTH direction in the UK too, so that bit was rubbish. As for switching, yes, UK appliances may only have single pole switches however this should only really be a problem if you are opening them up to work on them. In everyday use it should make no difference. Anyway, all the appliances in my UK caravan appear to be made for a European market. The fridge, heater and water heater all come with multi-lingual user manuals, so I assume they are the same as fitted across Europe. All appliances I use, chargers, TV, etc, are all either designed to work in Europe, or are completely sealed. The only potential problem I can see is the kettle, which is probably too power hungry for the site electrics anyway.

I really can't see where the problem is. Has anyone actually experienced ANY problem with so called 'reverse polarity' in France?

George

 

[rob_jax]

Hi George,

I believe the reason for the advice to check for polairty reversal lies at the decision to fit single action MCB (only breaks the live wire) devices in UK caravans and homes.

European caravans and homes have dual switching MCB devices which cut both the live and the neutral.

There is the possibility that if an appliance develops a fault in a UK caravan in Europe - and if the caravaner decides to poke about inside without unplugging the device - then the cheaper (by a few pence) UK MCB may have left the appliance live.

So it's good practice for the owner of a UK made caravan to correct the polarity - but the owner needs to do perform additional un-safe operations to really make it a danger.

And a note on appliances - double insulated appliances (usually the one's that don't have an earth connection) only switch one wire - in Europe and the UK. Earthed appliances in Europe will switch both the live and the neutral.

So looking at our caravan fridge - as one example of an earthed appliance - the 240V switch (dual action) is twice the width of the 12V switch (single action) because of the extra space taken for the dual switching.

Robert

 

[George2]

Hi Robert,

Yes I think that's what I was trying to say, the only real problem arises if you try to do something outside of 'normal' or 'safe' operation of the appliance.

I haven't looked at my fridge switching, but from what you say, you seem to be implying that that is correctly switched for safe European use.

George

 

[rob_jax]

Hi George,

Yes I believe so.

Perhaps the only difficulty is that you can't check every appliance (kettle, microwave, etc) for dual switching - they should be - but I know some aren't

And also that people do some funny stuff when trying to "fix" electrical problems - and I know people like to follow common sense - but every electronic appliance for the past 50 years shouldn't work from the common sense point of view (how transistors work).

So I have reservations about applying common sense to problems that require a more detailed understanding - hence the need for "competent" persons

Robert

 

[WatsonJohnG]

Certainly the site we visit every year in Brittany does not have curcuit breakers on both live and neutral

They are in either the live or neutral apparently at random.

A point about adapters and apologies if this has been said already

You need only one 2 pin adapter for French sockets .

There is no point in having 2 as the polarity reversing can be done with a short lead that has a blue euro plug on one end and a blue euro socket on the other.

You will need this anyway for sites that have the euro sockets and reverse polarity

I use the French 2 pin adapter at the site box end when needed and the reverse polarity lead at the caravan end with/without the 2 pin adapter depending on the site box .

 

[WatsonJohnG]

There is more here with pictures

http://www.ukcampsite.co.uk/chatter/display_topic_threads.asp?ForumID=7&TopicID=118731&PagePosition=1&showActive=8&ReturnPage=Active

 

[George2]

"Certainly the site we visit every year in Brittany does not have curcuit breakers on both live and neutral

They are in either the live or neutral apparently at random."

I think that would go back to what was said above, with two pole switching, it doesn't matter which side it's on.

As for 'polarity reversers' my question was are they really required, the name is certainly misleading, since there is no concept of 'polarity' with AC current, it flows in both direction 'alternately', hence the name.

I'd forgotten that Franch sites have different plugs though, how common are these, are they just two pin, and can they be inserted either way round ?

George

 

[WatsonJohnG]

Hi George

It wouldn't matter with 2 pole switching on the site electrics but my point was that it isn't 2 pole switching on all sites.

The French 2 pin plug has a socket for a pin on the site socket so it can not be reversed.

If you can get the link up that I posted above it shows a picture on page2 of the hybrid schuko/French plug which can be used in France and Germany as well as other European countries

All the adapter leads I have seen in UK shops use this hybrid plug but if you bought a standard German Schuko plug it would not go into a French socket as it doesn't have the socket for the French earth pin to go into.

Similarly if you tried to use a standard French plug in Germany it would not have the side earth contacts for the German socket

 

[WatsonJohnG]

Hi George

It wouldn't matter with 2 pole switching on the site electrics but my point was that it isn't 2 pole switching on all sites.

The French 2 pin plug has a socket for a pin on the site socket so it can not be reversed.

If you can get the link up that I posted above it shows a picture on page2 of the hybrid schuko/French plug which can be used in France and Germany as well as other European countries

All the adapter leads I have seen in UK shops use this hybrid plug but if you bought a standard German Schuko plug it would not go into a French socket as it doesn't have the socket for the French earth pin to go into.

Similarly if you tried to use a standard French plug in Germany it would not have the side earth contacts for the German socket

They are very common but being replaced with the blue Euro plugs gradually

 

[JeremyClarksson]

Alternating current does flow in both directions but normally in the UK and I suspect most places abroad at some point one wire will be connected to earth this is the Neutral or Return Path.

The live wire will then have 240V ac on it so the current on that will flow both ways but think of it as Live and Neutral not +ve and -ve.

If a current leakage device (RCB or RCCD) is fitted it compares the current in the live wire with the current in the neutral wire and trips if there is a difference i.e. leakage to earth through an appliance or person.

I think where polarity matters is if your caravan circuitry has the neutral bonded to the local earth in the form of the caravan chassis and then you connect the supply the other way (reverse L and N) there is potential to get shocks from the caravan chassis or metal work if stood on wet ground for example.

 

[rob_jax]

Hi George,

The French power socket seen at some (maybe half?) campsites is (or should be) the exterior version of the similar household socket. This has a better IP rating than the household connector, but not as good as the blue IP44 rated connector.

The term "polarity reversal" is totally wrong and inconsistent with AC power, but it's a happy compromise and metaphor for many people with a only rudimentary understanding of electricity - people who are probably are at home with the +ve and -ve terminals on batteries.

Robert

 

[Lutz]

French two pin wall sockets that are designed with an earth connection have a pin at the top. Standard (European) round plugs can therefore only be inserted one way round in such sockets. Flat 2 pin plugs without earth which are used on a lot of low power electrical equipment can, however, be insterted either way round.

Most other European countries have 2 earth contacts at right angles to the two pins, so you can always insert any European plug either way round, regardless of whether it has an earth connection or not.

 

[WatsonJohnG]

Alternating current does flow in both directions but normally in the UK and I suspect most places abroad at some point one wire will be connected to earth this is the Neutral or Return Path.

The live wire will then have 240V ac on it so the current on that will flow both ways but think of it as Live and Neutral not +ve and -ve.

If a current leakage device (RCB or RCCD) is fitted it compares the current in the live wire with the current in the neutral wire and trips if there is a difference i.e. leakage to earth through an appliance or person.

I think where polarity matters is if your caravan circuitry has the neutral bonded to the local earth in the form of the caravan chassis and then you connect the supply the other way (reverse L and N) there is potential to get shocks from the caravan chassis or metal work if stood on wet ground for example.

Also if you have any single pole switched appliances such as say a table/lead lamp in say an awning you could complete the circuit to earth in the event of reverse polarity.For less than

 

[George2]

"If a current leakage device (RCB or RCCD) is fitted it compares the current in the live wire with the current in the neutral wire and trips if there is a difference i.e. leakage to earth through an appliance or person."

So would the TEST button on the RCD device still cause a trip if the live/neutral are reversed ?

 

[RonD]

Yes!

 

[JeremyClarksson]

From memory the test button leaks a little current from the live side to earth through a resistor thus causing an imbalance so on the strength of that alone yes BUT if you have a 2 wire supply and there is no earth path through the caravan probably not as there will be no leakage current.

If however you provide a leakage path by for example touching the chassis while on damp ground than it should trip regardless of polarity, although that does not mean it is safe to assume it is safe as you would still get a shock if the polarity is reversed.

It is over 20 years since I did all this so if anyone knows better or things have moved on please correct me.