Cable Size Info Please

Discussion in 'The Beginner' started by oldflemo, Apr 5, 2015.

  1. oldflemo

    oldflemo Funster

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    I want to install a 12 volt socket,fused and directly off the leisure batteries and a second leisure battery. The socket will be within 1M of the batteries. Load normally 25mA.
    Also battery to battery cable size please -they will directly beside each other.

    Just wish I could remember my whole one year of electrical engineering study some 40 years ago but I can't!(sound like Orville!)

    Help please with cable sizes and appropriate fuse!
    Thank you in advance
    Ian
     
    Last edited: Apr 5, 2015
  2. Zains Pops

    Zains Pops Funster

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    Are you sure of the 25mamp load. It is exceptionally low to be concerned regarding cale size..
     
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  3. scotjimland

    scotjimland Funster Life Member

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  4. oldflemo

    oldflemo Funster

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    Yes it's simply to run an electronic mouse repeller and that is it's stated load
    Ian
     
  5. oldflemo

    oldflemo Funster

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  6. scotjimland

    scotjimland Funster Life Member

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    wet string.. ;)
     
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  7. Lenny HB

    Lenny HB Funster

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    As long as the fuse is a lower rating than the cable, for your use anything will do.
     
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  8. John Laidler

    John Laidler Funster

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  9. PeteH

    PeteH Funster

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    That is an ESSENTIAL. IF connecting batteries to form a "Bank" the cable BETWEEN batteries Must be adequate to conduct the maximum current. otherwise a "Big Draw" from one could cause the connecting cable to overheat (a Bit like your Toaster) With potential for Fire and or explosion.

    Pete
     
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  10. oldflemo

    oldflemo Funster

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    Was intending using 25mm cable for this the batteries will be immediately together. Will this be ok?
    Thanks Ian
     
  11. pappajohn

    pappajohn Funster Life Member

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    Wire the socket for its full potential....10 or 15amps depending on type bought.

    Doing that you are then covered for any eventuallity.

    1 mtr from source should be ok in 1.5mm or 2.5mm cable
     
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  12. TheBig1

    TheBig1 Funster Life Member

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    25mm2 cable would be suitably oversized for most motorhomes, however you need to fuse the positive in case an accident allows it to short to ground. also buy the cables already terminated for you unless you have suitable crimping equipment.

    having said that, the most common battery cable size is 16mm2 and will handle up to 110amps. tonnes of these on ebay £3<. again it needs to include a fuse for safety if long enough to touch earth if it became disconnected
     
  13. oldflemo

    oldflemo Funster

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    Thank you for this--- really appreciate the kind help you and the others on this great site freely provide
    Ian
     
  14. oldflemo

    oldflemo Funster

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    Can I ask if I've got as planned two 110 amp batteries what size should the fuse be?
    Thanks Ian
     
  15. Moodybrook

    Moodybrook Funster

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    I have 20A on mine which should prevent too much excitement happening when I don't want it to. I also wanted to limit the juice floating about and protect my Solar controller which is a 20A jobbie.

    I believe 25A is the standard.

    We are talking about the Positive between your two batts !
     
  16. PeteH

    PeteH Funster

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    To be fair. I am not sure I personally would bother, so long as the Cable can cope with the Current draw. Say 16mm2? or above. Care whenever removing a cable and disconnect the Earth(s) first before working anyway. and you should be OK.

    However. Any Fuse in the Main cable from the battery bank should be sized to cope with the Normal Current and the Surge current when a large item is switched on.

    The fuse rating In my Winnebago is 50Amp supply to the coach distribution box, according to the Wiring Diagram.? But I would caution that only as a Guide?

    If you want High capacity Fuses and Fuse Holders Try:-

    http://www.12voltplanet.co.uk/fuses-guide-uses.html

    And:- http://www.12voltplanet.co.uk/midi-strip-link-fuse-holder.html

    Pete
     
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  17. laird of Dunstan

    laird of Dunstan Funster Life Member

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    the fuse should be sized to protect the cable , if the socket is 5a or what ever, run the correct size of cable and fuse it to that size , the fuse in the plug that feeds the mouse scarer should be sized to protect that .
     
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  18. TheBig1

    TheBig1 Funster Life Member

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    the above posts about cable and fuse size refer to the battery bridge cable. the size of this depends on maximum rated current of attached equipment. generally people go with 25A unless there is an inverter or B2B charger fitted
     
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  19. oldflemo

    oldflemo Funster

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    Thanks that's great
    Ian
     
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