Reversed polarity

mrp62
mrp62 Forum Participant Posts: 44

Hi 

Off to France in a few weeks time . How common  is the problem of reversed polarity. And what is the best equipment to combat  the problem and where can I get it.

Cheers

«1

Comments

  • olden
    olden Forum Participant Posts: 38
    edited April 2016 #2

    Quite common. To correct it you need a mains tester to show that the polarity is reversed and if it is, a short lead, to fit into your EHU cable to reverse the polarity back again

    Try putting "reverse mains polarity" into an Ebay search to see some examples

    If the polarity is reversed your appliances are still live, even when the switch is turned off, as the switch would break the "Neutral" wire rather than the "Live" wire, as it would in the UK.

    So not a major problem unless you start poking around your appliances with a screwdriver

  • EJB986
    EJB986 Forum Participant Posts: 1,153
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    edited April 2016 #3

    Some say it's life or death...some say it's never caused a known problem since caravanning began.

    As an ex spark I am with the latter.Winking

    PS. Virtually everybody who thinks it is a problem will leave all their home appliances on standby....even when they go on holiday!

  • Lutz
    Lutz Forum Participant Posts: 1,564 ✭✭✭✭
    edited April 2016 #4

    It depends on how your caravan electrics are protected whether it is at all a problem. Many newer caravans and all Continental ones have double pole MPC's, in which case it doesn't how the EHU is connected.

  • Chris1966
    Chris1966 Forum Participant Posts: 27
    edited April 2016 #5

    As far as im aware a problem will only arise if the electrical item has a problem, all it means  is when something is switched off at the plug it will still be live, i took all measure of leads to france on my first trip different wired plugs 2 pin three
    pin,all  sites i have stayed on were the same as here,on another note a caravan i bought came with a blue lead the owner had used it for 5 years in the uk when i tried a polarity tester it was reverse wired for the uk and it had been used for all them years
    with no problems.

  • DougS
    DougS Forum Participant Posts: 327
    edited April 2016 #6

    For our Swift with Sargent panel, I believe that the RP light also indicates a problem with the Earth connection (faulty or absent) So if swapping L & N doesn't fix it that may be the problem? Of course you hopefully have RCDs but, personally I want a decent
    Earth AND the back up of the RCD?

  • waltons
    waltons Forum Participant Posts: 9
    edited April 2016 #7

    If it bothers you that much, buy a 3 pin plug tester that indicates polarity ( looks like a normal 3 pin plug with neon lights on its face ) Aldi were selling some a few weeks ago, or fleabay under £4.etc.

    Then nip down to toolstation and buy a male and female IP44 - 250v-16 amp plug and socket, blue ( £3.90)and buy a meter length of 2.5mm artic cable and make your own reverse polarity lead. Make sure you swap live and neutral in one plug. Then simply make
    a label or have one made up stating "Reverse Polarity cable".  Job done.

  • Tigi
    Tigi Forum Participant Posts: 1,038
    500 Comments
    edited April 2016 #8

    I`m with Waltons, if you would`nt accept reverse polarity wiring in your house why accept it in your caravan.

  • Geejay
    Geejay Forum Participant Posts: 232
    100 Comments
    edited April 2016 #9

    According to Serjeant the Reverse Polarity light on the control unit is designed for UK conditions, where the earth and neutral are connected at the substation.  Mine lit up in Spain, but the rcd still tripped on test.

    According to Electrician's Forums and other reliable sources, the rcd will trip with/without an earth and with/without reversed polarity.

    So check your rcd and don't tackle electical repairs unless you know what you're doing.

  • eurortraveller
    eurortraveller Club Member Posts: 6,830 ✭✭✭
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    edited April 2016 #10

    I`m with Waltons, if you would`nt accept reverse polarity wiring in your house why accept it in your caravan.

    But  you do accept it in your house if you live in Europe,  or rent a holiday house there, or stay in a hotel, or use your hair drier in a campsite shower block. 

  • olden
    olden Forum Participant Posts: 38
    edited April 2016 #11

    I`m with Waltons, if you would`nt accept reverse polarity wiring in your house why accept it in your caravan.

    But  you do accept it in your house if you live in Europe,  or rent a holiday house there, or stay in a hotel, or use your hair drier in a campsite shower block. 

    My understanding is that in the UK the switch should work on the Live wire. In Europe the switch works on both the Live and Neutral wires simultaneously, which is why they wire the circuit up either way around.

    So while your European house/hotel/campsite may have the polarity reversed the Live is always interupted when the switch if Off

  • Oneputt
    Oneputt Club Member Posts: 9,145 ✭✭✭
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    edited April 2016 #12

    In the last 4 years only come across reverse polarity once, moved the cable to another port in the EHU tower and no problem

  • hitchglitch
    hitchglitch Forum Participant Posts: 3,007
    1000 Comments
    edited April 2016 #13

    I have posted on this before but I don't mind repeating myself if it is of benefit to somebody.

    For historical reasons believed to be due to cost saving on copper, UK wiring practice is rather different to continental Europe.  We have ring mains, fuses, and single pole switches and elsewhere they have radial feeds and double pole switches.

    If you have a fuse or switch at home in the UK it inerrupts the live conductor. So, if you switch off at a plug then you could in theory (not desirable) work on the appliance in safety without further isolation.  If the supply is reversed then the live wire is still "live" and if you stick your fingure in an appliance it could be nasty.

    HOWEVER, most modern caravans have double pole switches which overcomes the problem. All caravans have rcd's which should protect you if you do touch live.  The rcd will work irrespective of polarity, missing external earth etc.

    IF you remember to properly isolate a supply before doing any maintenance or repair - switch off at main isolator or take the plug out - then there is not a problem. If you don't remememer and you touch live then you should still be protected.

    A final point, there are many electric shocks and fatalities caused by people wiring plugs in correctly. Like connecting the earth to the live pin - daft but true.

    SO, by all means make up a reverse polarity lead provided you are competent and use the correct weather protected fittings.

    We come across RP every trip to the continent. I do nothing but it is an individual choice.

  • Tammygirl
    Tammygirl Club Member Posts: 7,957 ✭✭✭
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    edited April 2016 #14

    We are currently on a site in Spain, it has 'no earth' the continentals don't seem to bother. But just about every British vanner has asked 'are we safe' what should we do. OH was in the armed forces, they always set up an Earth cable from the trucks to
    the ground. If in doubt its an easy thing to do. Like Hitch we have come across RP on many sites while abroad, we have a tester and a short reverse polarity cable which we can use.

  • harryb
    harryb Forum Participant Posts: 1,536
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    edited April 2016 #15

    I have 3 walk sockets in my van none have a switch. so is there any difference. Not really

  • chasncath
    chasncath Forum Participant Posts: 1,659
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    edited April 2016 #16

    We are currently on a site in Spain, it has 'no earth' the continentals don't seem to bother. But just about every British vanner has asked 'are we safe' what should we do. OH was in the armed forces, they always set up an Earth cable from the trucks to
    the ground. If in doubt its an easy thing to do. Like Hitch we have come across RP on many sites while abroad, we have a tester and a short reverse polarity cable which we can use.

    The 'continentals' don't seem to bother because "ignorance is bliss". You need to connect your van chassis to earth, or stop using the supply. ( See CC advice). A simple way to achieve this is to use a jump start lead clamped onto some metal work underneath
    and onto a large tent peg driven as deep as possible into the ground. There may be other metal posts nearbye that you could use. Your earth warning should then be ok. This will ensure that the rcd works ok and at least will prevent the van chassis from becoming
    'live'. Stepping from ground onto caravan step is where the risk lies. That's why the Forces always ground mobile accommodation.

  • hitchglitch
    hitchglitch Forum Participant Posts: 3,007
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    edited April 2016 #17

    Are you sure it has no earth? Is there an earth cable in the connection to the EHU? The reason I ask is that some Spanish sites use an unusual electrical supply with no neutral (for the technically minded, this can be phase to phase 230v from a delta wound
    secondary transformer). This will often give a false reading of "no earth" on supply indicators in the caravan but it doesnt necessarily mean that there is no earth to the caravan. I believe that all the wiring standards are the same on the continent in requiring
    an earth.

  • Tammygirl
    Tammygirl Club Member Posts: 7,957 ✭✭✭
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    edited April 2016 #18

    Are you sure it has no earth? Is there an earth cable in the connection to the EHU? The reason I ask is that some Spanish sites use an unusual electrical supply with no neutral (for the technically minded, this can be phase to phase 230v from a delta wound
    secondary transformer). This will often give a false reading of "no earth" on supply indicators in the caravan but it doesnt necessarily mean that there is no earth to the caravan. I believe that all the wiring standards are the same on the continent in requiring
    an earth.

    No idea, the tester says no earth, everyones reads the same but as I said we've been here a week and no problems, not about to start checking the EHU's. Noted what you said about false readings.

  • Tammygirl
    Tammygirl Club Member Posts: 7,957 ✭✭✭
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    edited April 2016 #19

    We are currently on a site in Spain, it has 'no earth' the continentals don't seem to bother. But just about every British vanner has asked 'are we safe' what should we do. OH was in the armed forces, they always set up an Earth cable from the trucks to
    the ground. If in doubt its an easy thing to do. Like Hitch we have come across RP on many sites while abroad, we have a tester and a short reverse polarity cable which we can use.

    The 'continentals' don't seem to bother because "ignorance is bliss". You need to connect your van chassis to earth, or stop using the supply. ( See CC advice). A simple way to achieve this is to use a jump start lead clamped onto some metal work underneath
    and onto a large tent peg driven as deep as possible into the ground. There may be other metal posts nearbye that you could use. Your earth warning should then be ok. This will ensure that the rcd works ok and at least will prevent the van chassis from becoming
    'live'. Stepping from ground onto caravan step is where the risk lies. That's why the Forces always ground mobile accommodation.

    Smile 45 years in the Army 25 of them in REME I think I will trust him to know what he's doingLaughing

  • young thomas
    young thomas Club Member Posts: 11,357 ✭✭✭✭✭
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    edited April 2016 #20

    "All caravans have rcd's which should protect you if you do touch live.  The rcd will work irrespective of polarity, missing external earth etc."

    interesting, although i think we have double pole switches, i havent yet found the RCD. DD has a similar van and he couldnt find his either....

    perhaps this is a 'german van' (Carthago?) thing?

    Chas, does your Hymer have an RCD? 

  • hitchglitch
    hitchglitch Forum Participant Posts: 3,007
    1000 Comments
    edited April 2016 #21

    I guess I shouldn't make blanket statements since I have not looked in every make of caravan/motorhome, UK or European. I would suggest however that it would be unusual to not have one. No push to test button on any of the breakers?

  • young thomas
    young thomas Club Member Posts: 11,357 ✭✭✭✭✭
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    edited April 2016 #22

    I guess I shouldn't make blanket statements since I have not looked in every make of caravan/motorhome, UK or European. I would suggest however that it would be unusual to not have one. No push to test button on any of the breakers?

    not that i can find....we have three trip/breakers in the 'electrics' cabinet, along with charger, but no RCD and no mention in the handbook.

    DD and i exchanged photos of the cabinet contents and could find no RCD (as i know it) anywhere....

  • Vicmallows
    Vicmallows Forum Participant Posts: 580
    500 Comments
    edited April 2016 #23

    I would find it inconceivable that any 'van less than 20 years old would NOT have an RCD.  It is probably combined as the main incoming switch in the 'consumer unit'. It may not actually say RCD on it (though there will be symbols which indicate this) and
    it will have a test button.

    If you really do have a commercially built 'van without an RCD something is seriously wrong!

  • chasncath
    chasncath Forum Participant Posts: 1,659
    1000 Comments
    edited April 2016 #24

    We are currently on a site in Spain, it has 'no earth' the continentals don't seem to bother. But just about every British vanner has asked 'are we safe' what should we do. OH was in the armed forces, they always set up an Earth cable from the trucks to the ground. If in doubt its an easy thing to do. Like Hitch we have come across RP on many sites while abroad, we have a tester and a short reverse polarity cable which we can use.

    The 'continentals' don't seem to bother because "ignorance is bliss". You need to connect your van chassis to earth, or stop using the supply. ( See CC advice). A simple way to achieve this is to use a jump start lead clamped onto some metal work underneath and onto a large tent peg driven as deep as possible into the ground. There may be other metal posts nearbye that you could use. Your earth warning should then be ok. This will ensure that the rcd works ok and at least will prevent the van chassis from becoming 'live'. Stepping from ground onto caravan step is where the risk lies. That's why the Forces always ground mobile accommodation.

    Smile 45 years in the Army 25 of them in REME I think I will trust him to know what he's doingLaughing

    Hope we didn't appear to be "teaching Granny to suck eggs" - no offense intended. We've provided our own connection to earth using a stout wire and clips on Spanish and other sites. Many continental electricity suppliers do not supply an earth, just live and neutral, and you have to provide your own for your property.( an earth spike in the cellar). In UK the neutral is earthed at the sub station and the earth carried on the outer protective sheath. On some continental sites, the ehus are just not connected properly to include a local earth.

    We have an RCD, BB

  • Vicmallows
    Vicmallows Forum Participant Posts: 580
    500 Comments
    edited April 2016 #25

     

    not that i can find....we have three trip/breakers in the 'electrics' cabinet, along with charger, but no RCD and no mention in the handbook.

    DD and i exchanged photos of the cabinet contents and could find no RCD (as i know it) anywhere....

    I'm wondering if maybe you have three RCBO's ?  ... these are overcurrent circuit breakers
    combined with an RCD.

  • Unknown
    Unknown Forum Participant
    edited April 2016 #26
    The user and all related content has been Deleted User
  • hitchglitch
    hitchglitch Forum Participant Posts: 3,007
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    edited April 2016 #27

    Just to revert back to my "false reading" comment, the plug detectors are measuring polarity with respect to a neutral supply as per UK practice and, of course, the neutral is connected to earth at some point. If you have a phase to phase supply there is
    no neutral, no reference point and the detector gets totally confused. Therefore you could get any combination of lights from reverse polarity to no earth but they are all meaningless.  A commercial supply to a site should have an earth but there are still
    parts of the planet where this is not common practice, despite any regulations and wiring practices to the contrary.

    If no earth, you are protected inside your van by the rcd but there is nothing to protect the outside of the van if, say, there is a fault on your cable and it makes the outer metal live.

  • young thomas
    young thomas Club Member Posts: 11,357 ✭✭✭✭✭
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    edited April 2016 #28

    BB perhaps we should do the wet finger test.  Please let me know how you get on and what if anything trips Wink.

    OH just doing the washing up....ill run her through the process.....Surprised

    perhaps one of the small yellow buttons we 'ventured' earlier...

    ill try a little more research prior to 'detonating'......Undecided

  • Unknown
    Unknown Forum Participant
    edited April 2016 #29
    The user and all related content has been Deleted User
  • young thomas
    young thomas Club Member Posts: 11,357 ✭✭✭✭✭
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    edited April 2016 #30

    Good move BB, nothing like delegation.  

    We are off tomorrow returning end of May.  I suspect we may find some reverse polarity in France, not that I am going to check.  I will have internet access some of the time and will follow your exploits Laughing.

    take care both, enjoy the time in Plymouth and keep in touch with the tour highlights....Happy 

  • Tammygirl
    Tammygirl Club Member Posts: 7,957 ✭✭✭
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    edited April 2016 #31

     

    Smile 45 years in the Army 25 of them in REME I think I will trust him to now what he's doingLaughing

    Hope we didn't appear to be "teaching Granny to suck eggs" - no offense intended. We've provided our own connection to earth using a stout wire and clips on Spanish and other sites. Many continental electricity suppliers do not supply an earth, just live
    and neutral, and you have to provide your own for your property.( an earth spike in the cellar). In UK the neutral is earthed at the sub station and the earth carried on the outer protective sheath. On some continental sites, the ehus are just not connected
    properly to include a local earth.

    We have an RCD, BB

    ...No offence taken chas, OH did consider a spike but . . . . . .