Positive & Negative??????

Discussion in 'American RV's' started by old-mo, Oct 23, 2009.

  1. old-mo

    old-mo Funster Extra Special Life Member

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    Can one of you knowledgeable gentlemen tell me which is "Positive" & Which is the "Negative" wire ?

    I am putting a cigarette type lighter/socket so my lad can plug his gismos into along side his seat in the back rather than run extensions from the front cigarette/cigar lighter all the way back..

    I have taken one of the interior lights down above his seat and in between the cupboard floor and to where the light is fixed it is double skinned following the quite thick wire into this skin it leads to a sort of junction which in turn all the interior lights on this half of the RV go to,, and the wire is very very thick so I should be able to take off from these junctions to my new socket,,

    Now the wire to one junction is white and to the 2nd junction is green... but from the white junction goes a white wire to the light casing and from the green junction a black wire goes to the centre pin of the interior light..

    Which colour is likely to be "Positive" and which "Negative" I dont want to get it wrong as I believe it could blow his DVD player etc.:Doh:

    Sorry this is a bit long winded but awkward to explain..

    Thanks..
     
  2. hilldweller

    hilldweller Funster Life Member

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    Go and buy a meter for a fiver. By far the safest solution.

    But you can screw up on a digital meter. If the meter reads 12 then the black probe is connected to negative. If you see -12 then reverse the probes.

    ( won't read 12 but 12.5, 13.5 or even 14.5 you make sure no minus sign )

    >> a white wire to the light casing

    *probably* the negative but I wouldn't bet the house on it.
     
  3. tucker_j

    tucker_j Read Only Funster

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    Use a meter or a 12v probe, both available very cheaply from a car accessory shop. Meter reads + or - so you can figure out which way round, probe hooks onto the vehicles ground and lights up when you find the positive feed.
     
  4. scotjimland

    scotjimland Funster Life Member

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    Hi Mo

    White is negative on my RV ..

    But,. don't risk it .. I agree with the previous posts.. a multimeter is invaluable.. :thumb:

    jim
     
  5. Geo

    Geo Trader - Funster

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    White is NEG on mine too
    I would bet Brians house on it:thumb:
    Geo
     
  6. johnsandywhite

    johnsandywhite Read Only Funster

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    :Cool: White is NORMALLY Negative and Black is NORMALLY Positive (LIVE). :thumb:
     
  7. Geo

    Geo Trader - Funster

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    Ah!! but would you bet brians house on it :RollEyes:
     
  8. hilldweller

    hilldweller Funster Life Member

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    &**(*&^%&$ OFF and leave my house alone.
     
  9. hilldweller

    hilldweller Funster Life Member

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    A P.S. to this - I had a post like this pulled and a nasty comment from a mod on facts because it was clearly not up to their high standards.
     
  10. ian81

    ian81 Read Only Funster

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    Another factor to consider is current draw. Although the wires are relatively thick it could be due to the distance from the battery. If the wires aren't thick enough to handle the current the gizmos draw the voltage at the socket will drop possibly too low to operate them properly. Also the wiring to the lights will be fused and that fuse may not be rated high enough for the curren drawn.

    Although more difficult it would be safer and better to run a dedicated wire from the leisure battery to the new socket.
     
  11. Geo

    Geo Trader - Funster

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    And so it should be pulled, you have spelt it wrong
    OH $%*7 I cant say that :Doh:
     
  12. thehutchies

    thehutchies Funster

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    But only if you've connected the probes to the meter the right way round. :Laughing:

    Should we write a beginner's guide to the use of multimeters in motorhomes?
     
  13. hilldweller

    hilldweller Funster Life Member

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    It's true. I didn't think of that one.
     
  14. old-mo

    old-mo Funster Extra Special Life Member

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    Thankyou for all your help and responces.. :thumb:

    In view of the fact I no nuffink about electrics and thickness of wire.. :Doh:

    I think I will go down the road "ian81" suggested and run a new wire from one of the leisure battery`s, just to be safe..

    Thanks again.
     
  15. hilldweller

    hilldweller Funster Life Member

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    Make sure you put a line fuse next to the battery. 5 or 10A should do. If you use cable something like you find on an electric kettle you won't go wrong.
     
  16. old-mo

    old-mo Funster Extra Special Life Member

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    Thanks Brian,,, duly noted..:thumb:
     
  17. Geo

    Geo Trader - Funster

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    Following Brian's suggestion
    Mo now finds the electric kettle plug wont fit the rear of the cigarette lighter socket:Doh::Rofl1::Rofl1::Rofl1:
    Any more bright ideas Brian:BigGrin:
     
  18. hilldweller

    hilldweller Funster Life Member

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    Yeah, I'm going to nuke Mansfield. It's only an inconvenience getting to the A1 anyway.
     
  19. Geo

    Geo Trader - Funster

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    Been done already causing nearly a £1 worth of damage
    On the plus side
    The survivers now glow in the dark and pedestrian RTA's have halved:thumb:
    Geo
     

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