RED to RED BLACK to BLACK

Discussion in 'Tech/Mech General' started by Techno, Nov 8, 2015.

  1. Techno

    Techno Funster Life Member

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    I want my baby back :D NOT
    Joking aside
    Generally RED is +ve POSITIVE / BLACK is -ve NEGATIVE
    EXCEPTIONS include blue as +ve brown as -ve (German Vans) and others but generally if you are adding or creating from scratch either be aware and use the same colours or go with the above.
    Use a 12 volt meter to establish which is which. The red test lead is positive and the black negative, if you put them on the wires that you are investigating they will give a reading "X" if RED is on the +ve OR "-X" if polarity is reversed. So red on blue black on brown on a hymer as the example will read 12 volts or more rather than -12 volts
    IGNORE all confusing words like live and neutral! completely incorrect when discussing DC "Direct current" circuits
    This thread is ONLY about DC
    Current flows from +ve to -ve
    All circuits must have their own fuse. The fuse protects the wire from overheating or catching fire.
    The size of the wire must be more than big enough for the current it is expected to carry and the fuse smaller than the wire can handle continuously
    To control a circuit involves a switch on/off and this is always placed in the +ve and this too must be rated to carry the maximum current.

    This thread will grow legs and run :LOL:
     
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  2. pappajohn

    pappajohn Funster Life Member

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    WATT !
     
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  3. Lenny HB

    Lenny HB Funster

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    Nope sorry to disagree, but Electron current flow go from negative to positive, in practice it is not important and the general convention is to assume it flows from +ve to -ve this is because this is what they believed in the early days, it was years later they discovered they were wrong. :)
     
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  4. Jonkil

    Jonkil Funster

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    And fused nearest as possible to the supply.
     
  5. Don Quixote

    Don Quixote Funster

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    At last a post with a positive feed thats makes good reading. Keep them flowing in the right direction....................
     
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  6. andy63

    andy63 Funster

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    Electrons flow - to + lol
    It will run for ages :LOL:
     
  7. pappajohn

    pappajohn Funster Life Member

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    You mean like coffee and red meat is bad for you.....this week !

    Too many scientists with time on their hands.
     
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  8. Jonkil

    Jonkil Funster

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    Correct
     
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  9. SuperMike

    SuperMike Read Only Funster

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    Or as in an RV, white is negative and positive is black. Or any other combination they thought of at the time, depending on what they had available. Also they don't tend to use cable colours or numbering, so for example all cables going rearwards start and finish as black. It's up to you to work out which is what. o_O
     
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  10. pappajohn

    pappajohn Funster Life Member

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    All my blacks were numbered Mike, still doesnt make tracing easy.
     
  11. Jonkil

    Jonkil Funster

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    Generally it is wise enough to ignore wire colour in a 12 volt auto circuit... Colours and tracers are only relevant to wiring diagrams and usually change from source to consumer.

    In aircraft all wires (generally 28volt !) are all white !
     
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  12. SuperMike

    SuperMike Read Only Funster

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    Not my words, but .........

    When you SPECIFICALLY say CURRENT, you are referring to current in the sense that it was understood prior to the discovery that the actual carriers were negative.

    It actually is BOTH. Allow me to explain.

    EXTERNAL TO THE BATTERY (in the circuitry and wiring):
    Current ("conventional current" as you could state it to avoid ambiguity) flows from the positive terminal to the negative terminal.

    INTERNAL TO THE BATTERY (caution...!):
    Current ("conventional current" as you could state it to avoid ambiguity) flows from the negative terminal to the positive terminal.

    Think of the battery as a pump. Just as in a water pump, the water flows from low pressure to high pressure because the water is being re-energized by the actions of the pump. External to the pump, in the piping, the water flows from high pressure to low pressure, because the pressure drives the flow to occur.

    Similarly, with batteries:

    External in the wiring:
    The higher voltage "pushes" the current to low voltage.

    Internal to the battery:
    The battery re-energizes the current via electrochemical reactions as it is "pumped" back to high voltage

    Notice that I discussed all of the above without ever once saying "electron"?

    That is what you should do when using the word "current", as the word "current" is conventionally understood to mean what it meant to early researchers.

    Current is the hypothetical flow rate of positive charges that would create THE SAME FIELD EFFECTS as whatever charges are actually doing the flowing.

    That being said, hypothetical positive charges flowing north at a rate of 1.6 Coulombs per second ARE THE SAME CURRENT as 10 quintillion electrons (remember, the electron is negative) per second flowing south.

    The current in the above example is directed north. It doesn't matter which direction actual particles flow or which sign the actual particles are.

    Current direction is given by:
    (sign of charge) * (direction of charge flow)

    If sign of charge is positive, then the direction will be the same as the actual flow.
    If sign of charge is negative, then the direction will be opposite the actual flow.

    That being said...our primary understood carrier of charge is the electron, which is negative. Most man-made circuits are based upon electrons.

    BUT, this doesn't mean that ALL circuits are based upon electrons. Some are based upon positive sodium ions, like those in your brain and nerves.

    The point is, we need to be flexible and inclusive in our definition of current and charge. We have a convention. Remember what the convention is...it is based upon positive charges. Remember what happens when the sign isn't positive. Remember that it is FIELD EFFECTS that matter.

    Don't blame Ben Franklin for guessing wrong. In fact, some have the opinion that he did us a favor in being more inclusive.


    Confused, you will be !!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :whistle: o_O :sneaky: :LOL:
     
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  13. Techno

    Techno Funster Life Member

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    There are plenty of connection options. I like these batteries because they offer the traditional connection post but a threaded stud in addition. Even then there can be too many wires but this can be overcome with the addition of such pictured
    [​IMG]
    [​IMG]
     
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  14. Don Quixote

    Don Quixote Funster

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    I knew it I knew it........ there would be + postings and - postings............ Getting really charged up now.o_O
     
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  15. andy63

    andy63 Funster

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    These gadgets can be handy for tracing wires and locating breaks if you can access the wires
    Andy
    20151108_184933.jpg
     
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  16. pappajohn

    pappajohn Funster Life Member

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    Andy.....That pic must have been taken BEFORE you bought your clampmeter.
     
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  17. Techno

    Techno Funster Life Member

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    Whoa! neddy :LOL:
     
  18. Don Quixote

    Don Quixote Funster

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    I bought one of these for the wife to test sockets in MH - works a treat ( sorry Andy for messing your topic around I will stop now )
    vilkus-plug-it-in.jpg
     
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  19. Techno

    Techno Funster Life Member

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    [​IMG]
     
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  20. pappajohn

    pappajohn Funster Life Member

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    Thats cheating.
     
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