Choosing the right fuse/circuit breaker.

Discussion in 'The Projects Forum' started by Lightfire, Apr 5, 2011.

  1. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    OK guys,

    For example, I had a circuit breaker rated for 5 amperes. It means that I should not use more than eleven 0.4166667 amp rated bulb. Isn't it?

    Because eleven 0.4166667 amp rated bulb is consuming already total all 4.5833337 amperes.

    Please correct me if I were wrong. :)
     
  2. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    The bulb only pass that much current when it is lit and hot.

    The resistance of filament lamp is much lower when it is cold.
     
  3. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    But when the bulbs are all lighted, my chosen fuse is correct?

    Thanks!!!!
     
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
    971
    fuses typically shall be run at no more than 80% continuous. 5A fuse = 4A maximum continuous. I'd use a 7A fuse minimum.
     
  5. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    If your talking AC mains then your local code will dictate.
     
  6. MEJY1988

    New Member

    Sep 28, 2010
    1
    0
    Most Breakers are rated for 80% continuous load. Check the manufacturers cut sheets to be sure. This includes the types that are used in businesses and homes. Just thought I would throw in my two cents. :cool:
     
  7. saikat36

    Member

    Jan 28, 2009
    16
    0
    5A fuse enough for your circuit. Go ahead.
     
  8. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
    690
    21
    It's only 12 volts. So as saikat36 said, it's enough, I guess so too...
     
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