Plugging MBA charger into socket = Bright Blue Electric?

Discussion in 'MacBook Air' started by CardboardGiant, Jan 2, 2012.

  1. CardboardGiant macrumors regular

    Joined:
    Apr 15, 2011
    #1
    Every Time I plug my 2011 Macbook Air Charger into a socket (in USA or Hong Kong with an adapter), I see small blue electric for about 1 - 2 seconds as I half-way plug the metal bit into the socket. It usually appears between the socket hole and the metal prongs.

    Is this normal? I don't want to get killed by my Macbook Air one day...
     
  2. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #2
    It won't harm you, your charger or your Mac. It's just electric current arcing between the socket and your plug. Just plug it in quicker and you won't see it.
     
  3. CardboardGiant thread starter macrumors regular

    Joined:
    Apr 15, 2011
    #3
    Okay thank you :) that's reassuring.

    Just out of curiosity ... If i stuck my finger between the socket and prongs, would I die?

    I've only been shocked once (and it was an accident) when I was unplugging my Bass guitar amplifier from the socket and instead of holding onto the plastic "head", i held the metal prong. I didn't die but I felt a slight jolt.. my heart was pumping so hard.
     
  4. GGJstudios macrumors Westmere

    GGJstudios

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    May 16, 2008
    #4
    Not likely, but I wouldn't recommend trying it.
     
  5. BreakGuy macrumors 6502a

    BreakGuy

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    Nov 23, 2009
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    NZ, South Pacific
    #5
    Is the switch turned off when you plug in your charger? Having it off prevents the flow of electricity, thus preventing the arcing.
     
  6. daviddth macrumors 6502a

    daviddth

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    Australia
    #6
    Many US sockets don't have switches at all, so you can't turn them off. Odd I know, but we were shocked when we saw it a few years ago, in both old and new buildings.
     
  7. CardboardGiant thread starter macrumors regular

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    Apr 15, 2011
    #7
    That explains a lot.

    When I'm in USA i plug my MBA charger directly into the wall, not one of those multi-sockets because the shape of the charger takes up two holes out of four.. so there's no switch. I see the electric.

    In Hong Kong I remember plugging it with the switch on.

    Guess I'll be careful from now on.
     
  8. miles01110 macrumors Core

    miles01110

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    The Ivory Tower (I'm not coming down)
    #8
    It really doesn't matter. Unless you're wearing steel wool gloves and holding the plug very close to the receptacle, any arcing will not come close enough to cause electric shock.
     
  9. BreakGuy macrumors 6502a

    BreakGuy

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    #9
    Hell, if it's arcing when plugging something into it, what's gonna happen when a child comes along and shoves a fork or a knife into it?!
     
  10. CardboardGiant thread starter macrumors regular

    Joined:
    Apr 15, 2011
    #10
    I guess you could put blu-tac or double sided tape on the the macbook air charger, above the prong area.

    so it'll stick against the wall.

    I have a cat at home and he likes to wander around and sniff things in my studio apartment. I don't want to find a shocked cat when i come home.
     
  11. GekkePrutser macrumors 6502a

    GekkePrutser

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    Aug 18, 2005
    Location:
    Ireland
    #11
    It's not good for the plugs itself though, I often get this spark with mine when I plug it in and the prongs are rather scorched :)

    I know those switches aren't always available, in Europe they're also very uncommon, it's just UK/Ireland that do have them. An extension cord with a switch might help in that case.

    By the way the reason it does this is because it's rapidly filling up its capacitors when plugged in, they're a bit like very low capacity batteries that charge/discharge very quickly. It uses those to compensate for small power interruptions and remove ripples.

    The high current and thus arcing when plugging in is called 'inrush current' and is common for switched-mode power supplies. It's also dependent on the state of the sine wave at the precise moment when it's plugged in - as it's alternate current it could be anywhere on the sine wave at that moment. If the sine wave is near the middle (near zero volts) there is no such spark and the slow buildup of the voltage will charge the capacitors more gently. But if the sine wave happens to be near the top (for 110V it will be even higher than that, as 110V is the average, not the peak voltage), it will cause that inrush.

    That's why components such as electrical relays often have 'zero detection', which means they'll wait to switch on until the sine wave goes through zero again, which it does 120 times a second (for 60 Hz). But Power Supplies don't usually have this, it's not practical because those electrical relays also need power themselves.

    Anyway maybe it's a bit off topic but I just wanted to share that background and information as to why it happens only some of the time.
     
  12. theSeb macrumors 604

    theSeb

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    Location:
    Poole, England
    #12
    It makes a bang noise and produces some awesome light. I did that when I was 5 years old (Europe - 220 Volts). My dad had taken a plug apart from some appliance and I took one of the single prongs and put it in the socket when he turned around for a moment. I don't know what possessed me to do that.
     
  13. Steve.P.JobsFan macrumors 6502a

    Steve.P.JobsFan

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    Jan 27, 2010
    Location:
    Cincinnati
    #13
    One of the three electrical sockets in my bedroom is controlled by the light switch on the wall. I HATE it. The cool part, is I have a switch in my room with a label on the wall plate that says "Aux. Power". :p

    [​IMG]

    I don't plug computers into that socket because if I bump the switch... ZAP! Everything is off.

    Anyways, does it happen no matter if it's plugged into the MBA or not?
     
  14. ZipZap macrumors 601

    Joined:
    Dec 14, 2007
    #14
    I have no experience with foreign adapters and power systems, but....

    How slow are you plugging it in?

    If you are doing it pretty quick and is sparks, I would be concerned that there is a charger issue.

    I have never seen a spark plugging in my charger.

    So many here have awarped sense of right and wrong when it comes to electricity.

    There is another thread where folks are saying its OK to feel current when touching the metal shell of the MBA. Since when is it ever ok to feel current when you handle the case?

    Answer....NEVER.
     
  15. ftaok macrumors 601

    ftaok

    Joined:
    Jan 23, 2002
    Location:
    East Coast
    #15
    Interesting to know that other countries typically have wall sockets connected to a switch. What happens if you have your desktop computer connect to such a socket and someone accidentally turns off the switch? I'd hate to be in the middle of a work assignment and the power gets turned off.

    Anyways, in the US, households that have young children, should have safety plugs inserted into every wall socket that is within reach of children. Once inserted, they are pretty difficult to remove if you don't have long fingernails, plus they require a bit of effort to remove. I'd say that kids would develop the strength and dexterity to remove the plugs around 8 years old, by then, they're old enough to understand what electricity can do.
     
  16. theSeb macrumors 604

    theSeb

    Joined:
    Aug 10, 2010
    Location:
    Poole, England
    #16
    And in that same thread it's pretty clear that what people are describing is not current, but the texture of the aluminium.

    My MBP charger sparks when plugging into a double adaptor type thing and into the wall sockets in my house. It does not do it when plugging into the wall sockets in my apartment. It is not something that keeps me awake at night.
     

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