Power outlet spark while plugging iMac?

Discussion in 'iMac' started by Daikyouju, Nov 18, 2011.

  1. Daikyouju, Nov 18, 2011
    Last edited: Nov 18, 2011

    Daikyouju macrumors member


    Aug 29, 2010
    Hi guys, I'm really concerned about this:

    Is this normal?

    When I plug my brand new iMac 2011 to the house power outlet it produces an spark? I am worried because the AC plug blades are becoming a little fried (some little black marks and dents after every spark as if it's being chopped off by the electricity). Is this normal?


    Those sparks are going to damage my iMac?

    Is it worth it to get a new power cable? or should i ignore the small dents on the plug's ac blades?

    Note: I'm on 220V
    Many thanks for your advices,

  2. drambuie macrumors 6502a

    Feb 16, 2010
    The sparks you see are do to the inrush current due to the iMac's power supply capacitors charging. The amount of sparking depends on where in the AC voltage cycle the plug prong to socket contact is made. It would be greatest at peak AC voltage, and non-existent when the AC is crossing zero volts.

    The best solution would be to use a switched power bar, and use the bar's switch for turning the AC on and off. It would also reduced wear and pitting on the wall socket.
  3. Daikyouju thread starter macrumors member


    Aug 29, 2010
    Thanks for your reply. So, i shouldn't be concerned about this because it will not damage my computer, right? :)
  4. drambuie macrumors 6502a

    Feb 16, 2010
    No, it won't harm the iMac, but as I said, the best way to prevent pitting is to use a power bar with an ON-OFF switch. The in-rush will still happen, but the power bar switch can handle it.

    It may not be as noticeable on 220v power, but on 120 volts you would also notice incandescent lamps on the same circuit dim for a fraction of a second due to the voltage dip when the iMac is connected to the AC supply.
  5. iSayuSay macrumors 68040


    Feb 6, 2011
    Actually that happens with all electronic devices on our home, the bigger the power, spark more likely happens whenever you plug it into the terminal. And it's NORMAL.

    So ... yes, as my above post said, use a switch instead of plugging it directly each time you want to use it, safer and more neat too, no need to worry about "Oh shoot there goes the spark" .. , I understand it looks frightening.
  6. Daikyouju thread starter macrumors member


    Aug 29, 2010
    Thanks guys for all the replies. Now i feel less concerned about this. =)

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