# No more reversed polarity worries - I think



## tonyt

I've never been really convinced one way or the other about the real dangers of plugging into a reversed polarity line but for the sake of a tenner for a tester and a tenner for a reversing cable and 2 minutes checking, I've always made the effort to check and switch over if necessary.

I've just spent £4.09 and hopefully eliminated the "risk" completely.

My humble campervan has only one 3 pin socket which I've now replaced with a double pole socket from Screwfix - why didn't I do this before?

I know most more upmarket motorhomes have more than one socket but even so, at £4 a time I reckon it's got to be a good buy.

Anyone want to buy a switch-over cable?


----------



## chrisblack

i'm not up to speed on rev polarity, but have seen numerous references to it...

can I have an idiots guide please.

if I plug van in to charge batteries whilst in France and it is reverse polarity, will it

a. not work
b. charge battery fine
c. blow up the electrics

thanks

chris


----------



## GerryD

chrisblack said:


> i'm not up to speed on rev polarity, but have seen numerous references to it...
> 
> can I have an idiots guide please.
> 
> if I plug van in to charge batteries whilst in France and it is reverse polarity, will it
> 
> a. not work
> b. charge battery fine
> c. blow up the electrics
> 
> thanks
> 
> chris


Chris,
Everything will work, it changes the way that items are earthed, but as so many electrical products are no longer earthed back through the plug you are unlikely to notice any difference.
Gerry


----------



## tonyt

Don't worry, it won't do any of those.  

It's all about whether your switch cuts the circuit on one side or both sides.


----------



## chrisblack

thanks Guys... I can stop worrying now and looking on ebay for a French EHU cable..

Chris


----------



## Rapide561

*EHU*

Hi

Where did youbuy the gadget from? I bought one from Maplin last year but it was recalled and never replaced.

Russell


----------



## Fatalhud

GerryD said:


> chrisblack said:
> 
> 
> 
> i'm not up to speed on rev polarity, but have seen numerous references to it...
> 
> can I have an idiots guide please.
> 
> if I plug van in to charge batteries whilst in France and it is reverse polarity, will it
> 
> a. not work
> b. charge battery fine
> c. blow up the electrics
> 
> thanks
> 
> chris
> 
> 
> 
> Chris,
> Everything will work, it changes the way that items are earthed, but as so many electrical products are no longer earthed back through the plug you are unlikely to notice any difference.
> Gerry
Click to expand...

Hi Gerry its more to do with the fact that the live is usually switched and if polarity is reversed then it means there is potentially still a live at your appliance

The earth is the same

Alan H


----------



## inkey-2008

If it matters so much how come it does not effect the rest of Europe on 2 pin plugs do you ever see them check NO.

That's because it does not matter which way round the live is. 

All of the appliances you use are the same as you get in the rest of Europe. All are double insulated so no worries.

Andy


----------



## BJT

Reversed polarity is a UK problem. We use sockets and light switches that are only 'single pole' and are intended to be positioned in the live side of the circuit.
European systems use 'double pole' switches, which operate on both sides of the circuit.
The hazard is that an appliance, or light, can still be 'live' if the single pole switch is in the negative, or return side, of the circuit; and the circuit can be completed through the earth connection if you get fingers/tools etc in the way. 
For safety you need to check the polarity on european sites before connecting, and use the appropriate standard, or off-standard wired adaptor to ensure that the live side of the circuit passes through the live side of an MH wired with UK sockets.
I use a 'Martindale' circuit tester that I have had for years. Apart from circuit polarity it also checks for the presence of an 'earth'; and has proved useful on occasions. I once came across a site where there was no earth at all, this was indicated on the tester as 'earth fault'. This meant there was actually no safety protection at all, as circuit breakers need an earth to operate. Technically many work as 'balanced circuit' devices, ie the current through live and neutral is the same, and if a defect occurs and contact is made to 'earth' the circuit goes out of balance and 'trips'.
These devices are very sensitive, if you look at them their 'rating' is printed on the front, and is measured in milliamps ie thousandths of an amp. So 30 mA is 30 milliamps is 3 one hundredths, or 0.03 of an amp;
which gives you an idea of the small amounts of power they can detect.
No earth is the most dangerous situation these days, although years ago many houses did not have any earth to their electrical installation if fed from overhead cables down the street!
If no earth is present you need an earth spike, or complain to the site manager ( if you can speak the local lingo tech style that is).
Earth spikes need to go into the ground sufficiently to give a good low resistance, and may need to be kept damp to work in some soils. You might get away with a robust steel or copper clad spike at least 300mm long; but the more metal in the ground generally the better the earth.
Earthing used to give me all sorts of problems when I was in gainful employment, one site on solid chalk where we had to install some 11000/415 volt transformers we ended up rock drilling 50m deep into the chalk to get the earth reading down to a level that the technical safety trips would work on!!

Hope this explains some of the technical side of 'reverse polatity'.


----------



## Broom

Hi BJT

We don't have to keep the earth spikes damp any more we use Bentonite (might have spelt it wrong) it gives a lower resistance.

Just must add in this country we must stick to the correct polarity.

Best Regards
Broom


----------



## chrisblack

there's an interseting point you make in your posting - you refer to the uk 3 pin socket...

therefore I guess that in imports like mine, fitted with a single european 2 pin socket, then no worries?

chris


----------



## BJT

No, you are quite right Broom, it is Bentonite. I thought there was enough tech stuff in the post without Bentonite, earth resistivity, copper clad driving rods, null earth balance meters, etc., etc.....
Brain goes into 'tilt' with too much info.


----------



## Broom

Hi BJT

Going to show my age now, what about me ''bridge megger'' still hung up in the garage.

Just asked the young wiz kids which sit around me about one, all frowned.

I still think that correct polarity should be observed with UK accessories and sites.

Best Regards
Broom


----------



## tonyt

chrisblack said:


> there's an interseting point you make in your posting - you refer to the uk 3 pin socket...
> 
> therefore I guess that in imports like mine, fitted with a single european 2 pin socket, then no worries?
> 
> chris


Well that socket should be switched and being continental, the switch will be double pole so you'll be ok.


----------



## oldun

GerryD said:


> chrisblack said:
> 
> 
> 
> chris
> 
> 
> 
> Chris,
> Everything will work, *it changes the way that items are earthed, but as so many electrical products are no longer earthed back through the plug you are unlikely to notice any difference.*
> Gerry
Click to expand...

I must disagree most strongly with this statement.

Reversed polarity *has nothing whatsoever to do with earthing*.

It means that the earth and neutral wires are reversed hence a socket with a single pole switch (the usual type of socket) will have the switch and the fuse in the neutral line. This means that if you switch off the socket or if the fuse blows the item plugged into the socket will remain live even though the current will no longer flow.

Touching a live part of the item will result in a shock though you should still be protected by the rcd.

You can have reversed polarity with and without an earth connected.


----------



## Zebedee

This is no criticism of previous posters, but just an opinion.  

The problem with reams of technical jargon is that it often doesn't mean a lot to some folk, and simply serves to make them even more nervous than before. :?

In a nutshell, so long as you disconnect an appliance from the mains socket before poking around inside it you should be safe, whether its polarity is reversed or not!

I know there is always the miniscule chance that a wire will come loose and touch the casing (or something equally unlikely) but that's a risk I'm willing to take if it means I don't have to carry a bundle of three foot copper rods to hammer into the ground on Continental sites!! 8O

_(Bundle??? They ain't coming out again easily are they? 8O )_

And I make that ridiculous statement quite deliberately, as I was asked exactly that question by a worried Newbie we got chatting to on a French campsite. 8O _(You guessed! He had been reading the forums and magazines! :roll: )_

It's always better to do things correctly of course, but sometimes the cure is far more problematic than the ailment!! :roll:

Dave

P.S. I do use a plug-in tester, but only to check for an earth connection. I also know they are not completely reliable for this purpose, but a lot better than blind faith *because the earth connection most certainly is important.*


----------



## teemyob

*Reverse Polarity*

Hello,

We have had a lot of reverse polarity on mains abroad, mainly France, Italy and Spain.

I was going to consider a switch over unit but noticed on our Frankia the hook-up plug simply twists off and without any tools you can unclip the wires and swap them.

Not sure where you can get the plugs from, cannot seem to find them anywhere.

Trev


----------



## bobandjane

Hi Trev, you can get them in France.  Bob.


----------



## thePassants

[Moderately technical bit follows]

My little Fluke plug-in socket tester states: will only detect missing earth >200KOhms.

Which implies that anything less than that would show as 'OK'.

Those who know what "Zs" is, also presumably know the max for a circuit behind a B10 MCB is 4.6 Ohms.

Assuming that the earth resistance referred to by the socket tester is "R2"; anything more than a couple of ohms is dangerous.

Furthermore, the Fluke one says it can't detect a Neutral / Earth reverse. (can't vouch for other brands products; but Fluke stuff is not 5hite)

[End of moderately technical bit]

OK, plug-in testers; they'll detect L / N reverse, and complete absence of E, but anyone armed with one of these should not be under the impression that it vouches for the safety of a circuit.

Having said that; if I remember, I'll be taking mine with me to Europe in 2wks time, but only out of interest. I'm certainly not taking a thousand pound multifunction tester with me; it's supposed to be a holiday after all!

My advice is not to use appliances in (and especially out of) your motorhomes, which are not "Class 2" = Double Insulated = have a symbol of 2 concentric squares (inside each other) on them;

and of course, don't start tinkering with mains electrical stuff unless you know what the limit of your knowledge is.


----------



## CliveMott

If your RCD is double pole (which prety well all of them in motorhomes are) then you have nothing to fear with reversed live and neutral connections at the hookup. Irespective of which one is live any earth fault will unbalance the trip and cause it to open.


C.


----------



## lgbzone

tonyt said:


> I've never been really convinced one way or the other about the real dangers of plugging into a reversed polarity line but for the sake of a tenner for a tester and a tenner for a reversing cable and 2 minutes checking, I've always made the effort to check and switch over if necessary.
> 
> I've just spent £4.09 and hopefully eliminated the "risk" completely.
> 
> My humble campervan has only one 3 pin socket which I've now replaced with a double pole socket from Screwfix - why didn't I do this before?
> 
> I know most more upmarket motorhomes have more than one socket but even so, at £4 a time I reckon it's got to be a good buy.
> 
> Anyone want to buy a switch-over cable?


Hi

Putting it simply; if i replace the sockets in my hymer with ones that state they are 'double pole', then i don't need to be conserned about this at all?

thanks
lee


----------



## teemyob

*Poles*

Lee,

Yes you do, Reverse polarity can effect many things especialy electronics.

Should be correct polarity.

Trev


----------



## lgbzone

Thanks for that

So the safest setup is to have some sort of polarity tester and an adapter to switch polarity if needed.

Lee


----------



## ThursdaysChild

I was always told that a little wee-wee helps an earth spike do its job.


----------



## eddievanbitz

Does anyone know of any ever being electrocuted in a motorhome or caravan? out of curiosity? 8O


----------



## tonyt

lgbzone said:


> Thanks for that
> 
> So the safest setup is to have some sort of polarity tester and an adapter to switch polarity if needed.
> 
> Lee


Your Hymer, being of Continental origin, should already be fitted with double pole switches - just like all Continental domestic properties who certainly don't use polarity testers/switchover cables.


----------



## chasper

ThursdaysChild said:


> I was always told that a little wee-wee helps an earth spike do its job.





eddievanbitz said:


> Does anyone know of any ever being electrocuted in a motorhome or caravan? out of curiosity? 8O


The mind boggles!


----------



## thePassants

*Re: Poles*



teemyob said:


> Lee,
> 
> Yes you do, Reverse polarity can effect many things especialy electronics.
> 
> Should be correct polarity.
> 
> Trev


I don't know of any electronics that run off 230v AC, without a transformer; the transformer in the appliances power supply establishes it's own polarity.

Here's another way of feeling 'in control':

http://www.campervanaccessories.co.uk/mains-polarity-changeover-switch-caravan-motorhome-p-358.html?osCsid=c79a4e8a01600ac2f4ab9c8965f49093

Anyone tried one?


----------



## bertieburstner

*electricity*

so are we saying that if you have a continental motorhome you do not have to worry about reverse polarity?

confused 8O


----------



## parkmoy

> Here's another way of feeling 'in control':
> 
> http://www.campervanaccessories.co.....html?osCsid=c79a4e8a01600ac2f4ab9c8965f49093
> 
> Anyone tried one?


Yes I've got one fitted and they do the job. More importantly, they recognize faulty earth problems and start a continual buzz warning.


----------



## lgbzone

tonyt said:


> lgbzone said:
> 
> 
> 
> Thanks for that
> 
> So the safest setup is to have some sort of polarity tester and an adapter to switch polarity if needed.
> 
> Lee
> 
> 
> 
> Your Hymer, being of Continental origin, should already be fitted with double pole switches - just like all Continental domestic properties who certainly don't use polarity testers/switchover cables.
Click to expand...

Hi Tony

My Hymer has a few different types; there are continental style sockets, uk sockets that appear to me to have come with the Hymer, unless someone has made a brilliant job of intergrating them, and finally uk sockets which i can see have been added at a later date. the continental sockets i wasn't considering, but as you said £4.00 is peanuts to be sure that the uk sockets are double pole, i'd much rather be safe than sorry. i never thought for an instant that people in europe would use testers and switchover cables at home.

Are there two issues here, one being that double pole sockets are safer than single pole, this i can easily sort by changing the uk sockets (to be sure), and a second issue that the polarity should go the right way for the appliences

thanks
Lee


----------



## oldun

parkmoy said:


> Here's another way of feeling 'in control':
> 
> http://www.campervanaccessories.co.....html?osCsid=c79a4e8a01600ac2f4ab9c8965f49093
> 
> Anyone tried one?
> 
> 
> 
> Yes I've got one fitted and they do the job. More importantly, they recognize faulty earth problems and start a continual buzz warning.
Click to expand...

I had one and it worked well until I made the mistake of trying to use the switch to change polarity when several appliances were operating.

The result was a burnt out switch.

Take my advice and the advice of many others, switch all appliances off (to minimise the current flowing through the switch) before operating the switch.

Also remember that the changeover switch must be in the line between the external input socket and the consumer unit.


----------



## parkmoy

> I had one and it worked well until I made the mistake of trying to use the switch to change polarity when several appliances were operating.
> 
> The result was a burnt out switch.
> 
> Take my advice and the advice of many others, switch all appliances off (to minimise the current flowing through the switch) before operating the switch.
> 
> Also remember that the changeover switch must be in the line between the external input socket and the consumer unit.


For that very reason the instructions from Dave Newell when I had it fitted were to trip the RCD before connecting up, and if necessary then switch over polarity before resetting the RCD.


----------



## oldun

I have had quite a bit of work done by Dave and am aware of the advice he gives re the change over switch.

However when I fitted the switch in question to my caravan Dave was probably still in nappies so his advice was not then available.


----------



## teemyob

*cuted*



eddievanbitz said:


> Does anyone know of any ever being electrocuted in a motorhome or caravan? out of curiosity? 8O


May not get a reply from that one!

Trev


----------



## anallew

The last post is the reason I love this forum!

At the very point in the thread when I know I'm totally confused and out of my depth, the humour hits!

Ah, relief. I do, at least, get that!    

Ana


----------



## Lol65

*Reverse polarity cables*

Hi Everyone

Still not used to these forum thingys, so please excuse if I'm not posting this where I should be!

I have read loads of posts both here and on other sites about reverse polarity, and whilst remaining confused as to whether or not it would pose a risk to me on my travels to France and Italy, I decided that I didn't want to take the chance.

However, I didn't fancy making up my own cable, & no matter where I searched, I couldn't find any that were ready made, until I came across a listing on e-bay, from a chap who was selling a 3 pin reverse polarity cable with a polarity tester. I contacted him to say I wanted a 2 pin version & already had a tester, so he made me a 3 pin to 2 pin adaptor, which cost me £15 for the pair, and which I received within 2 days!

Marvellous - peace of mind at last.

I would highly recommend that you check him out:

REVERSED POLARITY ADAPTOR LEAD + 2 pin Euro adaptor 
Item Id: 130322468422 
End time: 02-Aug-09 19:39:08 BST 
Seller: 
handycables (230) 
100.0% Positive Feedback 
Member since 10-Sep-06 in United Kingdom 
Location: Bristol, United Kingdom

All the best

Lorraine


----------



## PeterandLinda

Hi

The adaptor cables are not normally sold because of H&S concerns - imagine what would happen if some innocent didn't know the cable was reversing polarity, and died! Normally you have to make these reversing connectors yourself. Personally I would always check the polarity and earth connection with a small plug in tester. In most of europe you can simply change the plug upside down, but a Euro plug has an earth pin on the socket which prevents that. In that case, you simply plug the reversing connector into the van and plug the normal connector into the reversing connector.

P&L


----------



## TDG

tonyt said:


> Don't worry, it won't do any of those.
> 
> It's all about whether your switch cuts the circuit on one side or both sides.


At last! Someone taking a common sense approach. There has been too much pontificating on this subject but, having said, that it is a quite technical subject but I think some may be proving the point.... " a little learning is a dangerous thing"
I am a marine engineer with a First Class Steam & Motor Certificate of Competency and am qualified to work on electrical generating and distributions system up to 6,600 volts.
However, the jobsworths probably would not consider me to have the right bits of paper to qualify me to offer advice on this subject so I keep quiet....... although it's difficult. But..............................
The thought of someone wee weeing on the earth spike may be helping :twisted:


----------



## pippin

Just to remind everybody that it is not really a case of reversed *polarity*.

That implies positive and negative in terms of DC.

We are *not* talking + or - here.

It is the case that in UK the so-called neutral wire is tied roughly to earth (ie zero) potential.

In fact usually this is done by directly connecting them together at the sub-station and again as the wires enter your house.

The so-called live or line wire carries the volts which, being AC , varies at 50Hz between approx 330 volts and zero (or earth potential) giving an average of 235V.

You would suffer a shock if you touched the line/live and either the earth or the neutral.

It would be safe (if there were no faults) to touch the neutral and earth -* but do not try it!.*

Because only the live/line wire is potentially (!!) dangerous that is the only one (in UK) that is generally switched at socket outlets and in appliances.

Trips of the over-current type are also generally single pole and only isolate the live/line wire.

RCDs generally only cut the live/line side as well.

As an aside they probably don't sense a fault if the neutral is not at earth/zero potential.

In most €U countries the situation is different.

The neutral wire may or may not be tied to earth or zero potential.

In fact there may be no real distinction between the neutral and line/live wires, just that there is 235V between them.

So, because either wire may be at anything up to 235V with regard to earth or zero it is necessary to switch, trip and generally isolate *both* of them.

That is why *all* €U circuits are double-pole (neutral and line/live) protected.

So, when we waltz across _La Manche_ and plug in our UK-spec motorhome into a blue or some other weird Shuko, Danish, French or Swiss socket, well that is where the uncertainty or danger lies.

What is live might not be and what should be neutral or zero may not be either.

Your fancy UK RCD and single pole trips and switches may actually be in the harmless neutral side leaving dangerous live voltages present in your van when you think all is safe.

That is why you are well-advised to use a socket tester.

It will show the state of affairs and indicate if you need to reverse the blue and brown wires in your hook-up lead, or use a purpose-wired adaptor plug-lead-socket assembly.

Incidentally, I think the most dangerous operation occurs when you are in the process of initially connecting up to the EHU socket.

It may well be wet.

The EHU socket will in all probability already be switched on.

You will be nicely connected through your feet and/or fingers to earth/zero and here you are firkling about in the rain with plugs and leads and sockets.

I personally check the polarity *at the EHU* socket with a neon screwdriver *before* plugging in.

I then make the adjustments to my lead, if required, and then socket it into the van *before* plugging into the EHU socket.

I then double-check with a socket tester in the van.

SAFE at last!

Now, most people use the word *polarity* but I think it is better to call it *POLARISATION* for want of a better expression.

Some of the above is simplified, so E&OE


----------



## homenaway

pippin said:


> . . . I personally check the polarity *at the EHU* socket with a neon screwdriver *before* plugging in.
> 
> I then make the adjustments to my lead, if required, and then socket it into the van *before* plugging into the EHU socket.
> 
> I then double-check with a socket tester in the van.
> 
> SAFE at last!
> 
> Now, most people use the word *polarity* but I think it is better to call it *POLARISATION* for want of a better expression.
> 
> Some of the above is simplified, so E&OE


Hi Pippin,

Interesting post but I certainly wouldn't trust a neon screwdriver  

One of our instrument technicians used to use one until one day it failed to indicate and he got a belt off a connector - and that one had been purchased from the largest *R*eputable *S*upplys dealer in the UK.

Double pole switched UK sockets are readily available in the UK, made by the main manufacturers such as MK and Crabtree and available from Screwfix etc.

Personally I use a plug in tester and a changeover cable at all campsites.
(but from the above story a neon in the tester could fail   )

where does this all end? 
Steve


----------



## tubbytuba

I'm a bit worried, I reversed my polarity last night and it juddered


----------



## geraldandannie

Well done Pippin for a complete and thorough explanation 

The bottom line is: it is _unlikely_ that you will ever come to any harm with polarity reversed on your van.

However, for the sake of a few quid and about a minute's worth of time when you're setting up, is it worth not checking it?

P.S. I have a £5 Maplins tester and a home-made changeover cable.

Gerald


----------



## pippin

Steve. I take your point about not trusting a neon screwdriver.

However, in this application you are testing the neon screwdriver simply by the fact that one pole should light it up.

If neither light it up, either the socket is dead or the neon is dead!
I always doublecheck it.

In actual practice I use a non-contact Fluke VoltAlert.


----------



## Montlebaum

I have just bought a tester (W4 20018 Mains Tester) where the instructions state "the tester only requires a small current to operate and therefore it does not always show up an intermittent fault. The socket can be tested when it is carrying a high current by using an adapter and plugging in a high current appliance and the Tester at the same time". I'm not sure what this means! Help!


----------



## spottycat

We're away to France next week for our maiden voyage and after reading the previous five pages, may well rub two sticks together on every site we visit......
This appears to be a well established community, with topics covering everything, but why is there no information on what campsites in France (or anywhere else for that matter) have this 'problem' of reverse polarity? It would be realy helpful to know the sites to avoid so to speak.


----------



## GEMMY

Mainly because it doesn't matter and easily overcome.

tony


----------



## pippin

Because it does not really matter to the Continentals (for the reasons mentioned in my lengthy discourse earlier) which way round the wires are connected.

You may find that on any particular site some EHU sockets are "normal" and others are "reverse" POLARISATION - not polarity.

It would be an impossible and futile task to compile a list.


----------



## tonyt

I've now fitted my double pole switch but out of habit still plug my tester in before hooking up - some may think that's a bit OTT but......... I was at a well equipped and apparently well maintained C&CC CS last week and my tester showed No Earth! - I moved to another pitch.

I shall continue to use my tester and sleep in peace as opposed to resting in peace.


----------



## oldun

GerryD said:


> chrisblack said:
> 
> 
> 
> i'm not up to speed on rev polarity, but have seen numerous references to it...
> 
> can I have an idiots guide please.
> 
> if I plug van in to charge batteries whilst in France and it is reverse polarity, will it
> 
> a. not work
> b. charge battery fine
> c. blow up the electrics
> 
> thanks
> 
> chris
> 
> 
> 
> Chris,
> Everything will work, it changes the way that items are earthed, but as so many electrical products are no longer earthed back through the plug you are unlikely to notice any difference.
> Gerry
Click to expand...

I find this post misleading and positively dangerous

I was under the impression that reversed polarity was where the live and neutral are reversed and therefore it has nothing whatsover to do with how anything is earthed.

Everything I have used has worked with reversed polarity and as far as I can see the only downside is that the fuse will now be in the neutral line so that when the fuse blows the equipment will stop working but live connection will still remain live and the equipment dangerous.

If the fuse blew due to a leakage to earth then you will be protected by the rcd.


----------



## oldun

tonyt said:


> Don't worry, it won't do any of those.
> 
> It's all about whether your switch cuts the circuit on one side or both sides.


Again another misleading and dangerous post - reversed polarity has nothing to do with single or double pole switching. Double pole switching will make the device safer when switched off and that is its only benefit.

To repeat myself - reversed polarity is where the live and neutral wires are reversed. Now the fuse will be in the neutral line (potentially dangerous) and a single pole switch will switch off the device whilst still leaving the device live.

A double pole switch will switch off both live and neutral thus making it dead when switched off. The problem, when switched on, with the fuse in the neutral line will still exist.


----------



## karlb

oldun said:


> tonyt said:
> 
> 
> 
> Don't worry, it won't do any of those.
> 
> It's all about whether your switch cuts the circuit on one side or both sides.
> 
> 
> 
> Again another misleading and dangerous post - reversed polarity has nothing to do with single or double pole switching. Double pole switching will make the device safer when switched off and that is its only benefit.
> 
> To repeat myself - reversed polarity is where the live and neutral wires are reversed. Now the fuse will be in the neutral line (potentially dangerous) and a single pole switch will switch off the device whilst still leaving the device live.
> 
> A double pole switch will switch off both live and neutral thus making it dead when switched off. The problem, when switched on, with the fuse in the neutral line will still exist.
Click to expand...

go then ill bite.......with a double pole switch fitted and the polarity is reversed where is the potential danger?


----------



## TDG

8O I've heard that tyres can be good insulators 8O


----------



## Pudsey_Bear

All this is very confusing with so many differing opinions.

My simple (I hope) question is, does it actually matter if you don't intend to bugger about with the electrics, and don't intend to use any electrical items outside the MH, and if so how?

We as don't use sites in the UK, but do have a (Honda) genny, so does this add any complications.

The MH has been rewired and 4 metal double sockets have been added, 2 of which are now only connected to an inverter, 2 are still connected to the 240v side of the MH electrics and are live and working when on EHU at home, there is also a European socket which has a 3 pin adapter in it, but I've never tried it, so not sure if it's still connected.

We do intend to do a big Europe trip in the not to distant future taking about 3 months, and will be using Aires etc, so this problem will become more relevant.

Is there a simple but effective test to indicate if the MH is going to have any problems before spending much needed dosh unnecessarily.


----------



## pippin

Right Kev - here is the definitive way to find out.

Get a 240V 13A mains plug with lead and cut off the insulation to reveal the three bare wires - brown, blue and green/yellow.

Plug it into the mains socket nearest to the hab door and extend the wire through said door.

Park your MH on some wet grass and connect up to your EHU.

Take your shoes and socks off and stand on said wet grass (liberally sprinkled with salt) just outside your habitation door.

Wet your fingers, again preferably with salt water, and touch the green/yellow wire first.

If the wiring is sound then you should survive that experience.

Now touch the blue wire.

If the polarisation is correct you should survive that test.

If not........... well the result will be obvious to everyone else except you.

If, however, you did *not* receive a fatal electric shock you can confirm that the polarisation *is* correct by then touching the brown wire.

Again, the result will be of little interest to you but at least the grieving Liz will know that the van electrics are correctly wired.

Obviously I am joking so:

*DO NOT TRY THIS AT HOME*

There is in fact a *serious message *because the above scenario could, indeed would, occur if there are wiring faults.

Get it checked professionally if in any doubt.


----------



## lifestyle

My control panel lights up red ,if reversed and can be quite annoying to the eye.
Whether it`s safe or not,it only cost 5/6 quid for a short piece of lead with male /female connectors ,wires reversed of course .

Les


----------



## cronkle

lifestyle said:


> My control panal lights up red ,if reversed and can be quite annoying to the eye.
> Whether it`s safe or not,it only cost 5/6 quid for a short piece of lead with male /female connectors ,wires reversed of course .
> 
> Les


I agree with you Les.

The experts can't agree so what hope have I. So, as you say, for a few quid that I have already spent and a few seconds on site I will use my 'reverse polarity wire' and detector thing. I like gadgets anyway.


----------



## Pudsey_Bear

pippin said:


> Right Kev - here is the definitive way to find out.
> 
> Get a 240V 13A mains plug with lead and cut off the insulation to reveal the three bare wires - brown, blue and green/yellow.
> 
> Plug it into the mains socket nearest to the hab door and extend the wire through said door.
> 
> Park your MH on some wet grass and connect up to your EHU.
> 
> Take your shoes and socks off and stand on said wet grass (liberally sprinkled with salt) just outside your habitation door.
> 
> Wet your fingers, again preferably with salt water, and touch the green/yellow wire first.
> 
> If the wiring is sound then you should survive that experience.
> 
> Now touch the blue wire.
> 
> If the polarisation is correct you should survive that test.
> 
> If not........... well the result will be obvious to everyone else except you.
> 
> If, however, you did *not* receive a fatal electric shock you can confirm that the polarisation *is* correct by then touching the brown wire.
> 
> Again, the result will be of little interest to you but at least the grieving Liz will know that the van electrics are correctly wired.
> 
> Obviously I am joking so:
> 
> *DO NOT TRY THIS AT HOME*
> 
> There is in fact a *serious message *because the above scenario could, indeed would, occur if there are wiring faults.
> 
> Get it checked professionally if in any doubt.


I'm so pleased you find it a subject for amusement, I'm only disappointed that you didn't try it out first to check if it would work.

Obviously I am joking so:

Please try this at home.


----------



## TDG

Kev_n_Liz said:


> .................................Please try this at home.


Kev,
Surely that's only going to be safe if the reversing polarity camera is switched on :?: :roll:


----------



## TDG

Look - guys doing a practical risk assessment


----------



## pippin

Kev - I have had enough "belts" during my many years in electronics to know that I never ever want another one.

Didn't stop me getting one the other day - a "professional" electrician had cut insulation too far back leaving a cunningly hidden (to the eye) bit of live wire.

My finger found it!


----------



## tonyt

oldun said:


> Again another misleading and dangerous post - reversed polarity has nothing to do with single or double pole switching. Double pole switching will make the device safer when switched off and that is its only benefit.
> 
> To repeat myself - reversed polarity is where the live and neutral wires are reversed. Now the fuse will be in the neutral line (potentially dangerous) and a single pole switch will switch off the device whilst still leaving the device live.
> 
> A double pole switch will switch off both live and neutral thus making it dead when switched off. The problem, when switched on, with the fuse in the neutral line will still exist.


Can I suggest that you go back and read again what I said.

The double pole switch I fitted was IN ADDITION to the usual reversing cable which I ALWAYS check for and use where necessary.

I don't need a lecture thanks.


----------



## mothyinuk

*Schuko Wiring info and Effective RCD?*

Hi all.

This post, all seven pages to date, has been really helpful. It now explains why there is no information through Google to explain how to wire up a Schuko CEE7/7 plug except to point out the earth and the two live and neutral pins, but not which one is which!
I want to make up two conversion leads, one normal and one reversed, ready for a trip to Europe. Can any one say what is the normal way to wire up a Schuko plug and what is the reversed manner, because presumably the leads you can buy are normal, or are they?
Can any one shed some practical light on my wiring dilemma, thanks?
Also, I have just purchase an In Line RCD rated at 16amp from CPC, see following link…
http://cpc.farnell.com/pro-elec/inlinercd/rcd-in-line/dp/PL10474?Ntt=PL10474
Would this item still be effective using a Schuko supply where normal or reversed wiring is used?
All info would be really helpful.
Tim.


----------



## CullodenMuir

I'm a chartered electrical engineer so I SHOULD know what I'm talking about!

Reversed polarisation is where the live and neutral wires are reversed at the supply point. In this situation the fuses within the motorvan will be in the neutral wire rather than in the line wire and whilst a single pole switch will switch off the device, it still leaves that device live - dangerous should the device be faulty or should you you decide to work on the wiring believing it to be disconnected.

A double pole switch will switch off both live and neutral making the device it serves dead when switched off, but the problem remains when it is then switched back on.

Fitting double pole switches will protect you from a faulty piece of equipment supplied by that switch when it is turned off, but the fridge, the battery charger, the water heater, the space heater etc will all still be served by the reversed polarised supply.

So, when you meet a reversed polarised supply in Europe you do need to either insert a reversed cable length or use a polarity reversing switch to correct the supply to your vehicle.

Because the CEE 7/4 plug can be inserted in either direction into the socket, the Shuko connection system is unpolarized (i.e. line and neutral are connected at random). In this case a reversed polarised supply can be corrected by simply reversing the plug in the socket. However more and more sites in Europe are now using the blue 16A connection that is common in the UK.

An RCD will be unaffected by reversed polarisation, it works by comparing the current flowing on the line and neutral wires and if they are different it disconnects the supply. The difference required to cause the RCD to operate is very small, the intention being that a fatal current will be stopped at source before it can kill someone. 

Finally, any electrical wiring work has to be done by a qualified person OR certified by same, if something goes wrong there could be insurance/legal problems. If in doubt get a professional to do it for you!

John


----------



## clodhopper2006

*Re: cuted*



teemyob said:


> eddievanbitz said:
> 
> 
> 
> Does anyone know of any ever being electrocuted in a motorhome or caravan? out of curiosity? 8O
> 
> 
> 
> May not get a reply from that one!
> 
> Trev
Click to expand...

It happens. Just google "electrocuted caravan" without the quotes


----------



## mothyinuk

Hi John thank for your advise.

I understand your comments, but the Schuko plug I am going to use is a CEE 7/7 known I believe as a hybrid Schuko plug that can accommodate an earthing pin. When such a plug is used with a socket with an earth pin it is restricted in how it can be inserted and as such in this use the polarisation of the plug could be set. As I understand it even with this type of socket and plugs being used the live and neutral wires are still wired randomly in their respective pins.

However I found the following…

"Although Schuko sockets are unpolarized, it is recommended to wire them the same way most universal CEE 7/7 plugs are wired (live on left and neutral on right, when looking at the socket) for consistency and so that universal CEE 7/7 plugs will plug in polarized fashion in most cases (when the plug's female ground
receptacle is on top). However, there is no observed standard for that, so in most cases they are connected at random. That's why if there is a need to be sure which side is live, the socket's polarity must be tested every time."

All I want to know, is this true as finding information about correct wiring is like trying to find hen's teeth!

Your advise would be appreciated.

Tim


----------



## CullodenMuir

Yes Tim you are correct,

But you will only find the earth pin in parts of France and then the sockets will still be be wired randomly.

In this case you cannot simply reverse the plug in the socket but require either a reversing lead or reversing switch if the supply is incorrectly polarised.

John


----------

