reverse polarity

Discussion in 'Motorhome Chat' started by tilly ivimey, Aug 21, 2009.

  1. tilly ivimey

    tilly ivimey Read Only Funster

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    Hello, we are off to France in September in our new second hand VW camper. I,ve been told I need to check for reverse polarity when I hook up, can someone explain this to me, or point me in the right direction to find out? Many thanks in advance, Bill and Tilly
     
  2. johnsandywhite

    johnsandywhite Read Only Funster

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    :Doh: This is another one of those arguments that never gets sorted.

    I say 'IT MAKES NO DIIFERENCE'. WHY?

    The Microwave will not work the wrong way round.
    The Fridge/Freezer will NOT heat up instead of cooling down.
    The lights will NOT turn off when you turn them on. etc, etc, etc, etc in ad finitum.

    The ONLY difference is IF there is a problem with the wiring. ie: An Earth is connected in some way with the live or neutral and they get connected somehow.
    But THEN there will only be a problem if the Chassis is grounded and you touch the chassis or anything connected to the chassis.
    Also there is the possibility that IF the chassis is LIVE and it is RAINING? You MAY get a tingling sensation when you touch the bodywork. :thumb:
     
  3. Kon tiki

    Kon tiki Read Only Funster

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    You can get a plug with 3 LED's for checking the polarity heres one TOWSURE but they are readily available at most caravan dealers. They also show that the earth is working correctly.
    From what I understand the only problem is for UK designed motorhomes where we only have a fuse or trip switches on the live wire. On most continental vans they have trip switches which isolate both live & neutral wires so it isn't really an issue for them.
    The danger is in the event of blowing a fuse or a relay tripping & the polarity is reversed then the neutral wire is still live. You can either make a short fly lead with the wires crossed over if you find the polarity wrong.
     
    Last edited: Aug 21, 2009
  4. stagman

    stagman Deleted User

    It will make a difference . You will be switching the neutral instead of the live for a start .If a fuse blows the appliance will still be live . If an mcb trips the appliance will still be live .Please don't listen to people who say it won't make a difference buy a cross over lead it will only cost you a couple of quid and it could save your life :Angry:
     
  5. scotjimland

    scotjimland Funster Life Member

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    you forgot to mention that fans won't suck instead of blowing :Laughing:

    I agree with John, however, if you are concerned, buy a plug in polarity tester and a reverse polarity connector cable from any decent caravan supplies shop.

    When you hook up, plug in the tester, if it shows reverse then use the reverse polarity connector cable.

    jim
     
  6. Johns_Cross_Motorhomes

    Johns_Cross_Motorhomes Trader - Motorhome & Accessory Sales

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    There is a tester available cost £10-75 or an installed 'tester and changeover switch' at £39-99p.

    Peter
     
  7. stagman

    stagman Deleted User

    Well worth it as far as I am concerned :thumb:
     
  8. sinbad1

    sinbad1 Deleted User

    Ask yourself


    Would an electrician give a safety certificate for your 240v system if it was wired with polarity reversed?

    I doubt it, and IMO with electric or gas its not worth taking any risk . Best thing to do is seek advice from those that are qualified.

    Regards
     
  9. ips

    ips Read Only Funster

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    I totally agree, I have had at least two elecy shocks whilst working on equipment with reversed polarity when the isolator has been switched off. (Yes I know you shouldnt rely on the isolator neon and test it with a metre so yes its was my fault) Maybe it isnt a problem with your equipment working correctly but in the event of a fault as outlined by Mr stagman your neautral is still live regardless of your cb/mcb etc saying otherwise ???
     
  10. The Wallace

    The Wallace Read Only Funster

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    You are working in a van - all you need to do is pull the plug from the hookup if you want to work on the inside of any appliance - but how often do you need/want to work on the inards of an appliance when camping.

    My reverse lead is somewhere in my shed and will go in the bin when I find it - I have never found a reversed live/neutral (it's NOT bloody polarity!!) in weeks of camping on sites in France.

    If it makes you happy get a reversing lead but don't try the nanny state type scaremonger tactics on everyone else.
     
  11. Snowbird

    Snowbird Funster Life Member

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    Hi all,mabe someone can explain why my polarity tester works fine on hookup,but when genny is running all sorts of strange things happen to it,somtimes it tells me no earth,somtimes pos and neg reversed.
     
  12. twooks

    twooks Read Only Funster

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    can't help Snowbird, or anyone else with tecchie questions,
    but we frequently come across it, can't understand how some people can claim never to have encountered it in all their years touring - we often get different response from different connections on same branchement

    simply wire up a length of lead to cope with reversal o live / neutral, if nothing else it stops the little red warning light getting on my nerves. :cry:


    but - more importantly, come on England :Laughing::Laughing::Laughing:

    :thumb::thumb::thumb:
     
  13. pappajohn

    pappajohn Funster Life Member

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    possibly not a smooth enough supply.

    is it an invertor genny (kipor/honda) or a straightforward 230v AC (builders/B+Q/Aldi genny)
     
  14. Wildman

    Wildman Read Only Funster

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    for a tester to show the polarity (with respect to earth) an earth must be connected, if your Genny is not connected to an earth spike you will see variable readings. If it is mounted in the van it must be bonded correctly to earth (the chassis).
     
  15. Snowbird

    Snowbird Funster Life Member

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    Hi John,Its the built in Onan,You had the pleasure of listening to it at Malvern:BigGrin: Remember the security visit:Wink:
     
  16. Wildman

    Wildman Read Only Funster

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    you are missing the point. pos and neg are the same yes but one side is connected to earth so should you be quoting with respect to earth. now in the event of a fault the fuse is in the wrong line and your chassis/all metalwork in the van will become live. Thereby able to deliver you a shock under fault conditions only. Some electronics are very dependant on polarity with respect to earth so also needs protecting. A/C current is exactly that alternating current current flow in the cable is constantly changing direction. What makes one live and one nuetral is the fact that one side it tied to earth, the other side is fused. Hope that explains it. (City and guilds 224 and HNC (M.elec)
     
    Last edited: Aug 21, 2009
  17. Losos

    Losos Read Only Funster

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    The truth is out there in the above posts, but there is a lot of smoke and mirrors too :Rofl1:

    Basically, in some parts of Europe it is standard to wire the Live and Neutral of the wall socket opposite to what is the standard in UK, that is why you may sometimes need a Live / Neutral reverse lead.

    How do you know ? get one of those £10 testers, worth every penny.

    The smoke and mirrors ? Well that's when talk of the earth wire surfaces, yes occassionaly there may be an earth fault but even in the 'backward' parts of Europe the 'leccies usually get that wire in the right place :Rofl1: and once again the £10 tester will tell you and that's when you tell the site owner or move somewhere else :RollEyes:

    Is talk of 'polarity' correct, well that is a subject that could be discussed for weeks on end. Polarity on DC circuits is understood, on AC it's not 'quite' the correct terminolgy, but many people couldn't care less (I do care but that's hardly relevant is it:Rofl1:)
     
  18. Losos

    Losos Read Only Funster

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    Good point Roger, yes it is important to get it right, I forgot to mention above that you can get a shock from having the two wires reversed.

    What I don't like to see is talk about the earth wire being wrongly wired as in my experience that is quite rare (OK the neutral is taken to earth at the supply point but not usually anywhere else, or is it done at the consumer unit?)
     
  19. stagman

    stagman Deleted User

    sad
     
  20. The Wallace

    The Wallace Read Only Funster

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    Wow that's informative.
    IS this situation not unique to the UK where it is a left over from our early DC supply?

    Since our van has Shuko outlets then live / neutral has no meaning since the plugs can be inserted any way up. Therefore it is scaremongering to tell everyone to use so called 'polarity' changers.

    Alan, HNC & BSc.
     
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