Cable Size Info Please

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

  1. IanF

    IanF Funster

    Joined:
    May 7, 2013
    Messages:
    2,228
    Likes Received:
    652
    Location:
    Redcar- N.Yorkshire
    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

    Joined:
    Sep 10, 2013
    Messages:
    747
    Likes Received:
    5,026
    Location:
    Chelmsford Essex
    Are you sure of the 25mamp load. It is exceptionally low to be concerned regarding cale size..
     
    • Like it Like it x 1
  3. scotjimland

    scotjimland Funster Life Member

    Joined:
    Jul 25, 2007
    Messages:
    28,995
    Likes Received:
    25,691
    Location:
    Suffolk
    • Like it Like it x 2
  4. IanF

    IanF Funster

    Joined:
    May 7, 2013
    Messages:
    2,228
    Likes Received:
    652
    Location:
    Redcar- N.Yorkshire
    Yes it's simply to run an electronic mouse repeller and that is it's stated load
    Ian
     
  5. IanF

    IanF Funster

    Joined:
    May 7, 2013
    Messages:
    2,228
    Likes Received:
    652
    Location:
    Redcar- N.Yorkshire
  6. scotjimland

    scotjimland Funster Life Member

    Joined:
    Jul 25, 2007
    Messages:
    28,995
    Likes Received:
    25,691
    Location:
    Suffolk
    wet string.. ;)
     
    • Like it Like it x 2
  7. Lenny HB

    Lenny HB Funster

    Joined:
    Oct 18, 2007
    Messages:
    6,957
    Likes Received:
    6,845
    Location:
    West Sussex
    As long as the fuse is a lower rating than the cable, for your use anything will do.
     
    • Like it Like it x 1
  8. John Laidler

    John Laidler Funster

    Joined:
    Jan 9, 2013
    Messages:
    9,069
    Likes Received:
    12,424
    Location:
    Plympton, Devon
    • Like it Like it x 1
  9. PeteH

    PeteH Funster

    Joined:
    Nov 22, 2007
    Messages:
    2,270
    Likes Received:
    2,792
    Location:
    East Yorkshire
    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
     
    • Like it Like it x 1
  10. IanF

    IanF Funster

    Joined:
    May 7, 2013
    Messages:
    2,228
    Likes Received:
    652
    Location:
    Redcar- N.Yorkshire
    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

    Joined:
    Aug 26, 2007
    Messages:
    30,268
    Likes Received:
    17,931
    Location:
    YO11 2BD
    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
     
    • Like it Like it x 1
  12. TheBig1

    TheBig1 Funster Life Member

    Joined:
    Nov 27, 2011
    Messages:
    7,937
    Likes Received:
    10,302
    Location:
    Dorset
    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. IanF

    IanF Funster

    Joined:
    May 7, 2013
    Messages:
    2,228
    Likes Received:
    652
    Location:
    Redcar- N.Yorkshire
    Thank you for this--- really appreciate the kind help you and the others on this great site freely provide
    Ian
     
  14. IanF

    IanF Funster

    Joined:
    May 7, 2013
    Messages:
    2,228
    Likes Received:
    652
    Location:
    Redcar- N.Yorkshire
    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

    Joined:
    Jul 7, 2013
    Messages:
    800
    Likes Received:
    651
    Location:
    Wet and cold place outside of M25
    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

    Joined:
    Nov 22, 2007
    Messages:
    2,270
    Likes Received:
    2,792
    Location:
    East Yorkshire
    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
     
    • Like it Like it x 1
  17. laird of Dunstan

    laird of Dunstan Funster Life Member

    Joined:
    Feb 15, 2015
    Messages:
    1,402
    Likes Received:
    3,785
    Location:
    lincolnshire
    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 .
     
    • Like it Like it x 1
  18. TheBig1

    TheBig1 Funster Life Member

    Joined:
    Nov 27, 2011
    Messages:
    7,937
    Likes Received:
    10,302
    Location:
    Dorset
    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
     
    • Like it Like it x 1
  19. IanF

    IanF Funster

    Joined:
    May 7, 2013
    Messages:
    2,228
    Likes Received:
    652
    Location:
    Redcar- N.Yorkshire
    Thanks that's great
    Ian
     
Loading...

Share This Page