I have a Retina MacBook Pro 13" early 2015 version. I noticed that when the MacBook is on charge there's a strange feedback when I run my fingers over the surface of the MacBook case to the right and left of the trackpad. As soon as I unplug the MacBook's power cable the strange feedback goes away. The feedback feels like there's a slight buzzing going through my fingers. Is this normal or should I schedule a Genius Bar appointment?
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Strange surface feedback when charging
- Thread starter Demonknight
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Seems it's the power adapter as the feedback is also on the Magsafe connector. I've booked a Genius appointment.
Save your time, and use the provided extension lead, it`s just the lack of earth when connecting directly with the power supply, all unibody Mac`s do this. If you choose not to use the extension lead, neither you or your Mac will have any problem 
Q-6
Q-6
I have experienced this with both my current 13" 2015 MPB and my 2013 11" MBA. It's nothing to be worried about.
it's even better if while you are touching your laptop, you stroke somebodies cheek or arm, they get to feel the 'buzz' too.
It may be common but I don't agree it's normal. Yes, my MBP does it but not a single other two-pronged metal appliance in my house does it.
Well pretty much all of Apple's aluminium products do it, so if consider it pretty normal.
Found this:
When you plug your iPad into a wall outlet (or any charger for that matter), you would think the current should go into the device alone. Well, it doesn’t. Some of the charge is dispersed along the metal case by design. Here is a comment on Apple’s forum quoted from Apple’s support team regarding this issue:
There is measurable AC voltage across the external metal parts when an iPad charges. The measured voltage is within the SELV (Separated Extra-Low Voltage) limit, which means that the iPad is safe to touch. Additionally, the touch current is within the safety limit according to UL/IEC 60950 (Safety of Information Technology Equipment).[1]
As I do not experience this here in the UK I would suggest it is an American domestic power issue and your use of 2-pin plugs. The first time I took a aluminium unibody to the States I found the sensation a bit odd, but then again I find the spark you get unplugging an iron in the States a bit rustic!
It does happen in the UK if you use the duckhead rather than lead
As Gav2k said, use the extended lead, as that is earthed correctly. The duck head adapter has no earth connection.
I have experience it in both the UK and USA, as well as in Europe.
THIS. EXACTLY THIS. I've had this many times on my old MacBook Air but have yet to experience it with my MacBook Pro. It was extremely dependent on what power socket I was charging on. In the Netherlands by the way. I had to touch the whole device to something like a steal radiator or a copper pipe to ground itself and it went away after that, for a short while that is. It's static electricity that jumps from an exposed power ping on the motherboard (or something similar) to the case which stores the charge until you discharge it with something conductive.