Reversed Polarity Light

Discussion in 'Motorhome Chat' started by Mark5204, May 24, 2015.

  1. Mark5204

    Mark5204 Funster

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    Hi. I am sure this has been discussed before so apologies. We are new to MH and have just came back from a weekend away at a site in UK ,
    Upon connecting to EHU our reverse polarity illuminated on our Sargent charger box. It was however fine at home on EHU.
    I ended up swapping the blue and brown wire over in on of the plugs and all was then fine with Reverse polarity light now extinguished. Was this acceptable to do? Would I need to keep doing this on various sites? Thanks in advance. Our Motorhome incidentally is a 2004 Swift Kon tiki.
     
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  2. Minxy Girl

    Minxy Girl Funster Life Member

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    You need to make up a short reversed polarity cable so that you can use this with your existing correctly wired cable. You just need the 2 end connectors and a piece of the same cable, then when wiring it up reverse the 2 cables, as you had to do for your temporary fix, in one of the connectors.

    A - Reverse polarity correction cable.jpg
     
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  3. Mark5204

    Mark5204 Funster

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    Thank you for your reply. How would I tell when hooking up if this cable would be necessary. At home on EHU all is fine.
     
  4. Minxy Girl

    Minxy Girl Funster Life Member

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    The same way you already knew that you had reverse polarity on the site ... your Sargeant charger box would show the little light. Alternatively you can use the below 'red' tester (item 1) along with a 3-pin socket (item 2) and if you also get a continental adaptor (item 3) you can use this abroad too for either reversed or correct polarity EHUs:

    G - Testing continental hook-up point.jpg
     
  5. sinbad

    sinbad Funster

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    Is there a problem with having reverse polarity other than a safety issue though the RCD should provide protection in any case.
     
  6. pappajohn

    pappajohn Funster Life Member

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    Only if you work on an appliance without unplugging first.

    Switching off isn't enough as you are switching the neutral wire, not the live wire which will still be live.

    Electric is reversed half the time anyway....that's why it's call....ALTERNATING CURRENT ... or AC for short

    120v+/0v/120v-......50 times per second
     
  7. icantremember

    icantremember Funster

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    It is certainly worth having a plug-in socket tester which will, apart from polarity, show up earth faults that will also cause the light to show on your Sargent panel.
     
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  8. rupert

    rupert Funster

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    not sure how reverse polarity is detected with AC .but i have found this light is illuminated if you plug in with a poor earth
     
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  9. sinbad

    sinbad Funster

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    My understanding is that the neutral is earthed at the generator side so should be of similar voltage to a local earth e.g. in a house you have an local earth rod.
    The RCD will trip if the current flowing though the live and the neutral is different.
     
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