Finger "jumps" when touching the aluminium shell

Discussion in 'MacBook Air' started by ad1815, Aug 27, 2013.

  1. macrumors member

    Oct 30, 2012
    When I move my fingers on the aluminium shell, I feel that my finger "jumps" on it. I only feel it when the Mac is connected to a power supply; I don't feel it when the computer is disconnected from the power supply.

    Anyone has the same feeling? Anyone knows why?
  2. macrumors member

    Mar 13, 2005
    Ames, IA
    I've noticed the same thing. The computer is electrically grounded through the shell, so I would image a little bit of electricity is leaking out through your finger. I've tried to show it to other people but they never seem to be able to feel it. I imagine it might go away if you used a grounded power plug, like the extension cable that came with the power supply. Never tried though.

  3. jqc
    macrumors regular

    Jun 30, 2007
    I feel this on my 2010 MBA as well as when my iPhone 5 is charging (the back aluminum part)
  4. macrumors 6502a

    Jan 5, 2011
  5. macrumors regular

    Aug 4, 2005
    Gothenburg, Sweden
    Nope, both my MBAs (2011 and 2013) exhibit this behavior. It's very easy to feel. The behavior is normal when not having the unit grounded.
  6. macrumors 6502a

    Mar 11, 2011
  7. macrumors 65816

    Apr 17, 2012
    Destin, FL
    Happens when I touch my GF and my mac at the same time. No kidding.
  8. macrumors 604


    Jan 26, 2008
    Isla Nublar
    I don't feel it on my Macbook Air but I felt it on my Macbook Pro.
  9. macrumors 603


    Sep 19, 2003
    Canada, eh?
    Noticed this too on my 2007 MacBook Pro. Doesn't happen all the time. Maybe it happens when the outlet I'm plugged into is badly grounded. Could also have to do with the way the MagSafe connector is seated. One time I felt the tingling and then when I reached over to disconnect the MagSafe connector and re-connect it, I got a painful shock when I touched it. Looks like it may have been seated incorrectly.
  10. macrumors regular

    Jun 23, 2013
    United Kingdom
    I've read a previous thread that mentioned this issue is sometimes corrected when using the longer lead with the MagSafe power adapter due to the grounding :confused:
  11. macrumors newbie

    Aug 30, 2013
    This is because the power adapter you are using does not have grounding . Change it with a connector that has 3 "pins" will solve the problem.
  12. macrumors regular

    Aug 4, 2005
    Gothenburg, Sweden
    It doesn't just fix it sometimes, it always fixes it. The longer lead has ground pins, which the other plug doesn't. As long as the wall socket is actually grounded, it will make the issue disappear. For this reason, I always use the long lead.
  13. L T
    macrumors 6502

    L T

    Feb 24, 2013
    I've noticed that when my MBA is charging and I plug in my powered external hard rive the metal end of the USB sparks on the aluminium


    How about in the UK? All of our plugs have 3 pins!
  14. macrumors 6502a


    May 31, 2007
    The Garden State
    My white MacBook would do this when I would touch one of the screws in the plastic, I'd get a little zap that wasn't static.

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