Reversed Polarity Light

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

  1. Mark5204

    Mark5204 Read Only Funster

    Joined:
    Jan 20, 2015
    Messages:
    229
    Location:
    Bristol
    Ratings:
    +61
    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.
     
    • Like it Like it x 1
  2. Minxy Girl

    Minxy Girl Funster Life Member

    Joined:
    Aug 22, 2007
    Messages:
    12,229
    Location:
    E Yorks
    Ratings:
    +20,720
    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
     
    • Like it Like it x 1
  3. Mark5204

    Mark5204 Read Only Funster

    Joined:
    Jan 20, 2015
    Messages:
    229
    Location:
    Bristol
    Ratings:
    +61
    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

    Joined:
    Aug 22, 2007
    Messages:
    12,229
    Location:
    E Yorks
    Ratings:
    +20,720
    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 Read Only Funster

    Joined:
    Jun 3, 2014
    Messages:
    64
    Location:
    Tring, Herts
    Ratings:
    +89
    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

    Joined:
    Aug 26, 2007
    Messages:
    31,070
    Location:
    YO11 2BD
    Ratings:
    +23,098
    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

    Joined:
    Sep 2, 2010
    Messages:
    5,928
    Location:
    Nr Watton in Norfolk
    Ratings:
    +12,131
    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.
     
    • Like it Like it x 3
  8. rupert

    rupert Funster

    Joined:
    Nov 23, 2014
    Messages:
    128
    Location:
    leeds
    Ratings:
    +166
    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
     
    • Like it Like it x 1
  9. sinbad

    sinbad Read Only Funster

    Joined:
    Jun 3, 2014
    Messages:
    64
    Location:
    Tring, Herts
    Ratings:
    +89
    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.
     
Loading...

Share This Page