current leakage on MBA

I've noticed this on all of the aluminum Apple notebooks that I've owned. (12" PowerBook, 17" MacBook Pro, 11" MacBook Air).

anand.rohira said:

guys, i have got my new MBA from HONGKONG for 9600 HKD(the base model)

its pretty good and m very satisfied....everyone is amazed to see my new laptop, as its still not very popular in india, so its a very new thing, when i show it to my indian buddies.


anyways here is a small problem that I have:

whenever my laptop is plugged to AC power and I run my hands over the MBA, i feel a mild tingling kind of sensation, as if there is a small current leakage or something....

can you guys try this on your MBA,
(when its plugged in to socket, just close the lid of your laptop and run your hands over the lid, you will feel a mild vibration , tingling kind of sensation,.....and when your hands are still ober the MBA, there is no tingling sensation or anything present....)


so can you guys tell me what is it ?
is there something wrong with my peice ? or its just a common thing present in all MBA !!

Hope to hear some positive replies !!

Anand

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Ive had it on one of my laptops. Its actually not electrical (at work we had the electrician test it with some device). Its really weird. I know the exact sensation your describing. It goes away. (At least mine did).

All of my apple alu models (3 x air and 1 x pro) feels like that when on AC.

Perhaps it's the material...

I notice this too but I don't think it's electrical either. I believe it's the texture of the aluminum and/or paint/polish they use. It does feel like a vibration and strange but I've never noticed it to cause any issues or be a faulty electrical problem.

Is this not just because you bought it from a territory where AC power doesn't have an earth pin in the plugs?

If you use a grounded plug this will not occur.

I have that problem too. Anyone has any solution yet? the current leaks on my machine in spite of using the magsafe adapter. It works fine in Singapore but not so in India

Don't think it's grounding...

Fuchal said:

If you use a grounded plug this will not occur.

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Given that the magsafe PSUs all use a two conductor plug (between the removable pins and the body of the PSU) I don't really see how this would help. In addition I am in the UK where we have three pin plugs and have felt this sensation with every metal MacBook I've owned or used.

Alec

Yeah, got mine today and am so stoked! couldnt have been happier with the performance. that being said, every mac i have owned (the black polycarbonate being an exception) gives me the same sensation when I run my hand over the machine. Using a 3-pin plug didnt help either. What I want to know is if this affects the mac in any way. Anyone?

It is normal to feel voltage on the external case when it is plugged in. The Mac won't be affected at all by it.

Sorry, but it NEVER normal to feel current when you touch the case.

This is a known issue with Alu Macs... most PC/Mac motherboards use a floating ground, so basically you are becoming ground when touching the Alu chassis, drawing current from the chassis to yourself. Not much you can do about it unless you run a grounding strap to the Mac itself.

Hmmm, I don't feel anything. I do have it plugged into a power surge protector all the time when on AC.

I have it on my 11" when not using the grounded plug. If I lightly brush my hand across the top part of the front of the lid while its open and running, (Above the Apple) I can feel it.

It feels like running wet hands against dry glass.. kinda hard to describe.

it is just the effect of your friction ridges skittering across the sand-blasted type finish. all my macs have done it.

EDIT.

I was utterly wrong, read my post below.

I get the same plugged in, not plugged in, on or off. It's the surface texture and I love it..

Hmmm. I have altered my opinion about this. I have made some odd discoveries, I get the odd juddering, tingly feeling when my MBA is plugged in, but not when I unplug it. I also did some experiments whilst the machine was plugged in; if i am experiencing the effect on the left side of the track pad and then with my other hand touch the other side the effect disappears. If I pick the machine up, whilst plugged in, the phenomena fails to appear. But if i pick the air up using my sleeve to prevent me touching the air (other than the odd sensation seeking hand) the sensation is discernible.
I had the same odd sensation when I used to own a MBP, but I never thought about it much or undertook the researches I just have done.
I feel it all the time if a digit touches aluminium whilst moving between keyboard and trackpad.

So it MUST be something to do with stray electricity ambling about, else my earthing experiments wouldn't have given me the results they did. musnt they?

Oh, another thing is that the effect only occurs when moving against the surface, never when my finger or whatever (I still feel it when using an iPad stylus) is still.

Ive given the matter more thought, and as the effect only appears when moving a finger I was wondering if the air and MBP perhaps have a fan, which makes the case vibrate, and which only comes on when the machine is plugged in and my touching and holding the machine have stopped it being able to vibrate the case so easily?
Oh, another thing is that the effect only occurs when moving against the surface, never when my finger or whatever (I still feel it when using an iPad stylus) is still.

Fuchal said:

If you use a grounded plug this will not occur.

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Not True! The MBA power supplies have NO earth connection. Even if your cable has earth this earth is connected to....NOTHING!

It IS electrical: transfers between persons

This issue has always been present in all aluminum MacBooks, not just yours. It's nothing to worry about, but I agree that it can be annoying.

With all due respect - why would you only notice this phenomenon when the mac is plugged in, if the explanation had to do with the aluminum texture or paint, as several suggest?

The reason why I'm convinced it's electrical is that it transfers from one person to another! I kid you not, when my girlfriend is using her MBP while plugged in, I can tell when she's touching it and when she's not, without looking, by running my fingertips across her skin. If another person is touching the metal part of a plugged-in MacBook, you can feel the same tingling sensation on their skin as if you were touching the computer directly, although the effect is somewhat weaker.

tmoerel said:

Not True! The MBA power supplies have NO earth connection. Even if your cable has earth this earth is connected to....NOTHING!

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That is incorrect! There are different cables for the charger, some connect to the ground in the outlet and some don't. I believe that it is the metal pin visible in the picture below:
http://ii.alatest.com/product/full/6/7/Apple-60W-MagSafe-Power-Adapter-for-MacBook-0.jpg .

I've noticed this with all my MacBook Airs (I have had them since the first one in February 2008).

Okay, try this. Place your hand on the case. DON'T move it. Do you still feel a tingle?

The case has a texture so yeah you're gonna feel something...

That does not sound good at all! I've never experienced this!