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View Full Version : current leakage on MBA




anand.rohira
Mar 22, 2011, 02:34 PM
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



kepner
Mar 22, 2011, 02:41 PM
I've noticed this on all of the aluminum Apple notebooks that I've owned. (12" PowerBook, 17" MacBook Pro, 11" MacBook Air).

chrono1081
Mar 22, 2011, 02:59 PM
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

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).

latchiopal
Mar 22, 2011, 04:18 PM
All of my apple alu models (3 x air and 1 x pro) feels like that when on AC.

Moodikar
Mar 22, 2011, 04:40 PM
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.

JonLa
Mar 22, 2011, 04:57 PM
Is this not just because you bought it from a territory where AC power doesn't have an earth pin in the plugs?

Fuchal
Mar 22, 2011, 05:31 PM
If you use a grounded plug this will not occur.

anand.rohira
Mar 23, 2011, 08:05 AM
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.


nope, i don think, its texture or paint on the aluminium body of MBA,
if that was the case, i wud feel the same sensation if my MBA was dissconnected from power supply (but I DON'T !!)

i think , i will go home and try with the 3-pin, earth pin, and report u guys what happens !!

THANKS A LOT FOR YOUR PROMPT REPLIES !!
REALLY APPRECIATE IT
:)

abansal
Dec 29, 2011, 10:50 AM
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

AlecEdworthy
Dec 31, 2011, 06:29 AM
If you use a grounded plug this will not occur.
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

anirudh
Dec 31, 2011, 01:34 PM
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?

Puevlo
Dec 31, 2011, 04:43 PM
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.

ZipZap
Dec 31, 2011, 08:26 PM
Sorry, but it NEVER normal to feel current when you touch the case.

calvol
Jan 1, 2012, 01:24 AM
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.

ET iPhone Home
Jan 1, 2012, 01:53 AM
Hmmm, I don't feel anything. I do have it plugged into a power surge protector all the time when on AC.

Maven1975
Jan 1, 2012, 02:06 AM
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.

doktordoris
Jan 1, 2012, 03:45 PM
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.

daviddth
Jan 3, 2012, 03:46 AM
I get the same plugged in, not plugged in, on or off. It's the surface texture and I love it..

doktordoris
Jan 12, 2012, 07:00 PM
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.

tmoerel
Jan 13, 2012, 03:00 AM
If you use a grounded plug this will not occur.

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

recryl
Jan 14, 2012, 05:52 AM
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.

lindskogaren
Jan 16, 2012, 10:12 AM
Not True! The MBA power supplies have NO earth connection. Even if your cable has earth this earth is connected to....NOTHING!

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 .

KPOM
Jan 16, 2012, 10:33 AM
I've noticed this with all my MacBook Airs (I have had them since the first one in February 2008).

lolwut89
Jan 16, 2012, 11:23 AM
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...

gentlefury
Jan 16, 2012, 11:34 AM
That does not sound good at all! I've never experienced this!

samwich
Jan 16, 2012, 11:39 AM
I recently spent 6 months or so in Europe and noticed the sensation using a power converter from my US power adapter to UK. Back in the US, I don't feel the tingling sensation. Almost positive it has something to do with different power infrastructure/plugs in different countries.

lindskogaren
Jan 16, 2012, 11:47 AM
If you only have the two supply lines (neutral and phase) the potential of the outgoing ground to the macbook from the power converter may drift since there is no known ground reference. I.e. the common mode voltage of the + and - signals going to the macbook will be floating. I'm not sure why, but the common mode voltage often stays somewhere at 1/2 the outlet voltage. Probably has something to do with typical switched power supply topologies.

If you connect a third known safe potential (in this case, ground), the - pin going to the macbook can be connected to this potential which means that there will be no common mode voltage that feels uncomfortable.

The reason why the common mode voltage (lets say 150 volts) is harmless is because the maximum current is rather low.

jumper5
Jan 16, 2012, 12:29 PM
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

Hey Anand!
I'm from India as well, and a recent proud owner of an Air.

I understand what you mean. That happens to me as well when earthing isn't proper, OR I plugin the power source to 2-pin power source.

xCromwell
Jan 16, 2012, 02:39 PM
I've had that but on my iPad 2. I'll be getting my Macbook Air around the 20th and I'll also report on that ! :)

maril1111
Jan 16, 2012, 02:40 PM
Happens to me too I things its completely normal

doktordoris
Jan 16, 2012, 02:56 PM
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...

It is this fact which makes me think it is due to vibrations caused by a fan, rather than electricity spilling out over the machine. The effect is only felt by a moving finger. BUt the effect ceases when the power is disconnected.

recryl
Jan 20, 2012, 09:21 AM
It is this fact which makes me think it is due to vibrations caused by a fan, rather than electricity spilling out over the machine. The effect is only felt by a moving finger. BUt the effect ceases when the power is disconnected.

I agree that the phenomenon is only noticeable when the finger is moving, but the fact that it also occurs when running a finger across the skin of a person touching the plugged-in MacBook (without touching the machine yourself), convinces me that the phenomenon is electrical.

doktordoris
Jan 20, 2012, 02:25 PM
I agree that the phenomenon is only noticeable when the finger is moving, but the fact that it also occurs when running a finger across the skin of a person touching the plugged-in MacBook (without touching the machine yourself), convinces me that the phenomenon is electrical.

Hmm. You are right, if it works via another person it must be electricity based. I shall test this out.

vnvette
Feb 19, 2012, 03:45 AM
I'm on my 3rd MacBook Air in 4 weeks. The first 2 had other problems but not this particular problem. I'm an Electrical Engineer and am forced to use this thing for work. What you are actually feeling is about 5 Volts AC lingering on the case of the computer. I measured it so it's not the fan, not the paint job, but real live electricity that's leaking onto the case and into your body. Yeah, the 3 prong cable "masks" the problem, as does being an Apple fanboy or not knowing the first thing about electricity. Unfortunately, the fact is that this is a flaw and one that probably isn't so good for you.

steveza
Feb 19, 2012, 04:14 AM
Yeah, the 3 prong cable "masks" the problemHow does this work exactly ... the masking bit? If you have 5V DC going to the case and you earth the AC on the other side of a transformer, why would that stop the tingle? It's been a while since I studied electronics at college but I can't see why this should make a difference.

BTW: If you use the long cable on the other end of the transformer then it has an earth connection, all the other adaptor plugs do not ... this would appear to be a design flaw.