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Why is the fuse blowing?

  1. Feb 5, 2007 #1
    I have a circuit in my house that sometimes blows its fuse. Now, electricity is not my field at all so I'm asking you guys. I know the fuse is 10 amps, I use perhaps 3,5 kW on this circuit, and we have 230 V over here. Don't know if that's enough info to make any form of judgement on whether or not I'm using to much stuff on this circuit, but I don't know what else to tell you...
  2. jcsd
  3. Feb 5, 2007 #2


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    Just a thought, is the load an electric motor? Motors have a very high inrush that can trip a breaker, even though the nominal current is well below the breaker rating. (Inrush is the current when the motor is started and before it gets up to speed.)
  4. Feb 5, 2007 #3


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    ??? What am I missing here? 3500/230=15Amps
  5. Feb 5, 2007 #4


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    As Russ pointed out, 230volts X 10 amps = 2300watts, well below both of your predicted loads.
    Simply put, you have too much plugged in.
  6. Feb 6, 2007 #5
    Ah, now I get the equation at least. Obviously I must have overestimated the load. Thx guys :)
  7. Feb 7, 2007 #6
    10A sounds low for a 230V ring main. I would expect 15A or 30A
    What have you got connected to the fuse, Lights or Wall sockets? this is important as it will affect how you track down the fault.
    Do you know how many rings are in your house and how they are nominally connected?
    Also what country are you in? as whilst I can track down faults I am much better with UK type wiring regs than US type ones, and what the Greeks do frightens me.
  8. Feb 7, 2007 #7
    Easy peesy lemon squeezy. Overloaded circuit and fuse as already stated.

    As Panda mentioned 10A is an odd rating. Have a look to check the cable size the circuit has been run on is substantial enough to take the load. Don't just bung in a higher fuse and forget about it. Unless of course you want to run the risk of an electrical fire (you don't) :wink:
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