Going to France

[BensGrandad]

I have a burning ambition to take my old 1978 Sherpa Highwayman camper to France for a few days. I have no worries about the mechanical ability of it as I would jump in it and drive to Cornwall or Scotland from my home in Sussex without a worry.

 

I am a little concerned about electric hook ups in France as I am sure that I have read in this magazine and others that you have to 'change the polarity'. Is this just a case of wiring an extention lead the opposite way round i.e our live to their neutral and our neutral to their live as I do not think that they have any earth cables on their electric. Any advice would be greatfully received but please do not be too technical as I am not an electrician and have very little knowledge of this.

[ike]

If you use the search facility at the top of the page by entering "reverse polarity" it will bring up previous threads on this topic and will tell you what to do. We've used hook up many times in France and Spain and never experienced any problems and have never taken steps to check for reverse polarity. Maybe we've just been lucky.

[Basil]

Hello BG

 

You will only have to change polarity if it is wrong, you need a plug in tester (available at most good electrical shops, Screwfix or the like see one on the ECLeisure site below on the spares page) to find that out as it is not noticable under ordinary circumstances. Some would say it doesn't matter anyway, personally I don't subscribe to that view but have no intention to justify my reasons.

 

Probably the best route is to fit, or have fitted, a reverse polarity detector and changeover switch such as is available on

 

http://www.davenewell.co.uk/

 

click on 'Bits and Bobs, he does supply only I believe and only needs to be wired into the inlet supply this negates the need for the aditional tester or hook ups as it is a combined permanantly fitted unit, so is justifiable on the basis of cost if you have none of the bits and bobs already.

 

Or alternatively you can go to

 

http://www.eastcoastleisure.co.uk/

 

click on 'Mains Hook Ups' where you can find various plugs and sockets to make a short coupling with the 'Live' and 'Neutral' reversed on one end to be used between your normal hook up lead and the site socket. Whilst you are on that page you will see a ready made 'Continental Adaptor' that you may possibly require on some French sites at a reasonable price.

 

Bas

[Brian Kirby]

ike - 2008-02-23 1:07 PM If you use the search facility at the top of the page by entering "reverse polarity" it will bring up previous threads on this topic and will tell you what to do. We've used hook up many times in France and Spain and never experienced any problems and have never taken steps to check for reverse polarity. Maybe we've just been lucky.

But Irene, your two statements are mutually exclusive, no?  You have had no problem with reversed polarity, for which you've never tested.  Hmmm! 

The possible problems will only arise if there is a fault somewhere in your system or connected equipment.  If there is a fault that has developed while you are travelling, and you are unaware of it when you connect to a supply with its polarity reversed, you may encounter problems up to the severity of fire or shock.  However, if you test the polarity first, you can eliminate these risks.  It wont fix the fault, but at least the normal safety measures in your on-board system will be able to work as designed. 

However, if your van is new enough to have a residual current device (RCD) as its internal "mains" switch, the risks are almost irrelevant - provided there is an adequate earth connection.

To answer Brian's questions, with a 1978 van, unless the electrics have been modified, I'd be more concerned.  I think it at least probable his installation has no RCD, and he is therefore at some risk.  The best advice would be to get an RCD mains switch fitted in any case, as these are a major contribution to electrical safety.  Electrician if unsure!

Because of the way most continental European mains electrical supplies are wired, the "live" and "neutral" terminals have little significance.  UK installations are wired differently, and for safety it is much better to maintain live-to-live and neutral-to-neutral connections.  That poses a minor problem for us when we visit continental countries. 

First up, you need a tester.  You should find one in most caravan/motorhome accessories shops, often marketed by W4.  I guess the best advice is to plug it into a live socket clearly visible from the van door before you connect the hook-up.  Next up, you'll need a short length (about one foot) of hook up cable with the usual blue plug and socket at each end, but as you guessed, with the live and neutral reversed in one of the connectors. 

You should connect the van end of the hook-up cable first, so one of you needs to connect at the feeder pillar while the other watches which lights come on at the tester.  If the indication is "no earth" try a different pillar.  If you can't find one with a working earth, ask for your money for the hook up to be returned and don't use the connections!  However, if the tester indicates reversed polarity, disconnect the cable at the pillar, then insert your short length of cable, connecting first to the end of your hook-up cable, and then to the pillar.  Hey presto, polarity restored!

A further point is that with an installation of this age you probably have fuses rather than circuit breakers.  Do be aware that fuses take longer to react to overload faults than breakers, so it becomes even more desirable to be sure the polarity is correct, so that the fuse has the correct relationship to the circuit.

Finally, one potential problem with reversed polarity is that, unless corrected, the current will be flowing out through fuse/breaker in the intake "consumer" unit, instead of flowing in through it.  Thus, the current will flow through unprotected circuits.  In this way, in the absence of an RCD, a fault current can flow to earth and may cause severe overheating of the cables, or fire, before enough burns out to cut the flow.  With most site installations today there will be circuit breakers and RCDs an the pillar, but I'm sure I've seen a few that haven't yet been brought up to date!  So, safety first.  Get an RCD fitted, and ideally get the fuses replaced with circuit breakers.  Failing that get a tester, use it every time you connect to a new supply point - even if it is only the next socket on the same pillar - and take, and use as necessary, your magic polarity reversing cable.

Bonus item: you are still likely to need a continental two pin connector for some sites.  Same source of supply as the polarity tester. 

Many sites have now adopted the blue CEE sockets, but on our trip around France in 2006 about 30% of sites still had the two pin sockets, and about 30% of both types of sockets had their polarity reversed, so it isn't safe to assume you will be OK with new installations.

[ike]

Brian As ever your response is comprehensive and helpful. My comment was made out of ignorance. My not having experienced any problems really means I haven't yet electrocuted myself nor set the van on fire! Ours is a 1991 van and I have no idea whether or not it has an RCD. I can almost see you shaking your head at my sublime ignorance! I have printed your reply to show to hubby to persuade him we should have our auto electrician check things out for us and buy a tester kit. We've had vans for nigh on 20 years but because we haven't yet had a problem of this type there's no point taking unnecessary risks.

Thank you

Irene *-)

[rupert123]

Do not understand the worry with the so called reverse polarity at all. With direct current yes but surely all hook ups are alternating current which reverses itself about 50 times a second.

[tonyishuk]

rupert123 - 2008-02-24 4:35 PM

 

Do not understand the worry with the so called reverse polarity at all. With direct current yes but surely all hook ups are alternating current which reverses itself about 50 times a second.

 

I think the problem may be if current is traveling up your arm and down your leg when reversing itself at 50 c/sec. ;-)

 

Rgds

[hallii]

Get a good leisure battery and forget the mains connection, that's what I do, unless you want to run a microwave, 40" TV, electric cooker, 2kw heater and air conditioning.

 

And I doubt that you do. Electicity costs more money in France, my battery is free!

 

Geoff

[Brian Kirby]

rupert123 - 2008-02-24 4:35 PM Do not understand the worry with the so called reverse polarity at all. With direct current yes but surely all hook ups are alternating current which reverses itself about 50 times a second.

The simplest way to prove this is also rather dangerous!  So, the safe way is to say that your mains electrical supply has three wires.  One is normally designated "live", one "neutral", and the other, "earth".  In fact, both the earth and the neutral are, more or less, earths (they are, I believe, normally brought together at the local mains transformer, but in your indoor consumer unit the neutral is switched along with the live, whereas the earth, for obvious reasons, is unswitched.) and only the live carries the current.  Thus, you should never get a shock from either the neutral or the earth, but you definitely will from the live! 

With reversed polarity, the neutral becomes the live, and vice versa.  In UK installations, although the mains switch (or RCD if fitted) is a double pole switch, and so will isolate both live and neutral lines, the fuses (or miniature circuit breakers) are only installed into the live side of the supply.  Thus, all current enters your circuits via a fuse/MCB on the "live" side of the consumer unit, but exits via the "neutral" side unfused.  If polarity is correct, this is a perfectly safe arrangement. 

However, where polarity is reversed, so that the neutral wires now become the lives, the current flows to your circuits unfused, and only encounters a fuse on exit - not much use.  Under these circumstances, if there is a wiring fault and current is running to earth, the circuit wires can be dangerously overloaded and overheat.  And so will you if you happen to come into contact with one!

Continental practice is to install fuses into both live and neutral terminals at the consumer unit, or to use double pole MCBs.  Thus, for them, it does not matter which way the current flows round the circuits, because it will encounter a fuse on its way in, in either event.

The most significant safety factor has been the incorporation of an RCD into mains switches.  This monitors that the amount of current flowing in on the live side, is exactly equal to that flowing out on the neutral side (of your mains switch).  If the two currents become unequal, by even a few thousanths of one Amp, the RCD opens the main switch and isolates all current.  The logic is that the only way the two flows can be unequal, is if insulation has failed somewhere, allowing current to "leak" to earth.

So, with an RCD on the mains switch (identifiable by the presence of a "test" button) - provided the unit is regularly tested and works, and provided all other aspects of the site supply are in good order - the risks of shock or fire due to reversed polarity are almost eliminated.  However, note the two provisos, only one of which is within your control. 

Thus, the probability of fire or shock as a consequence of reversed polarity is quite low in the absence of an RCD, is hugely reduced by including an RCD, but is only eliminated in either case, if the polarity is corrected. 

Having said all that, I did encounter one site in France where the polarity spontaneously reversed at about 10:00 PM each evening, and reverted back again in the morning.  Our van has an RCD on its mains switch, and a continental consumer unit with DP circuit breakers so, as the site earth appeared sound, even this didn't seem to present a risk and I was happy to carry on using it.  However, anyone with a UK wired installation and no RCD, would have been wise to unplug!  But that's half the fun, you never quite know what you'll encounter next!