I have a MacBook Pro 4.1. In the past - from time to time - you could feel a bit of electricity close to the aluminium case when working in AC mode, but now things are getting worse. I can feel the electricity all the time, especially close to the opening button and to the corners. Talking with other MBP users, I have been told that the whole MBP 1.4 series has got this problem and that it is due to the presence of the aluminium case. Is it a known issue? Is there any workaround to properly ground the laptop?
The mac can only ground itself through the magsafe connector if you are using a grounded plug. In the us - the "duck head" two prong connector is ungrounded.
The adapter article from Apple has some good tips and a nice picture.
You shouldn't be able to feel any tingle due to you being better grounded than the mac if your outlet is properly grounded.
You'll have to check with an electrician or take your mac to another outlet that is known to be properly grounded if you are already grounding it through the wall if you still feel the tingle with a grounded cord.
This sort of ground current drives me nuts (even though it's normally totally safe). I have on occasion intentionally grounded one of the plastic feet with foil when I am waiting for the electrician to fix an outlet or I am working in a location where I can't get a proper ground.
Well I have just experienced this tingle on my Macbook Pro with the magsafe 85w power supply and the 3 pin plug lead with a UK 3 pin plug.
I could not believe that Apple would not earth the machine via the magsafe adapter, so I detached the power lead from the 85w power supply block and took a look how they earth it. The power supply block has a 2 pin connection for live and neutral and the earth connects via the 10mm dia stainless steel stud that the plug lead [or the plug with no lead] slips over to lock it onto the block. Then I saw the problem! On the end of the 10mm stud, the manufacturer had put a 12mm disk of protective plastic [the peal-off film type that you often find on say a new phone screen]. So in their efforts to keep the stud looking shiny and polished, they insulated it from electrical connection, that is they insulated the EARTH STUD !! Just peal it off, plug it back together and [unsurprisingly] there is no more tingle from the alloy case.