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Fuse breaking current

  1. Jun 19, 2010 #1
    Dear all , i have an important question which i need answer for it , if you look at a catalog for fuses you will find the fuse rated current which for example is 10 A

    and you will find a value called minimum breaking current and it is usually higher than the rated current for our example let's say about 15 A

    so what is meant by minimum breaking current , does it means the fuses will not disconnected
    unless a value higher than or equal 15 A which is higher than the normal rated current .

    and what will happen if a continuous current flow for a long time with value 13 A which is higher than the rated current and smaller than the minimum breaking current

    please help

  2. jcsd
  3. Jun 19, 2010 #2
    Low test current (I1) is defined as; the largest current the fuse can hold for one hour without breaking.
    High test current (I2) ; the lowest current which breaks the fuse within one hour.

    Not quite sure what minimum breaking current is, but i belive it must be I2. Not sure though, someone else might know.

    If you se a graph like http://www.buildingdesign.co.uk/elec-technical/hager-t1/18-hager-4.gif" [Broken]. I1 is 1.13A and I2 is 1.45A in a 1A fuse.
    Last edited by a moderator: May 4, 2017
  4. Jun 19, 2010 #3
    well , actually after doing some search i found this:
    the minimum breaking current is the minimum current that can cause the fuse to disconnect
    for example assume the normal current for a fuse is 10 A and the minimum breaking current is 15 A , so between this region the fuse cannot completely trip or disconnect so when you choose the fuse you must make sure that you are not going to work in this region .
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