[kogir]

Any properly grounded device will do that with specifically incorrect electrical wiring and/or a shoddy charger. Did this happen with a properly wired outlet, and an undamaged Apple charger?

I have doubts that it did, as that would warrant a safety recall.

[Liftyee]

Can confirm it does happen. UK, both on my ThinkPad and a friend's MacBook when plugged in. It's a somewhat unavoidable side effect of the switching AC adapter designs - the output is isolated from the mains, but there is a tiny leakage current that can sometimes be felt as a "vibration". This is completely safe (far below the currents needed to cause harm) and no recall is needed.

[cachius]

Thank you. I always felt this vibration and wondered what it was.

[mapmap]

If you replace the two prong plug on the AC adapter for a three prong cable, your MacBook case will be properly grounded and you won’t feel any vibration.

[raydev]

Cast aside your doubts, I've been to different parts of Europe a few times with different, healthy MBPs (I buy a new one every 4-5 years) with healthy adapters.

Plugging into the wide EU outlet with the Apple-manufactured plug, from the "World Travel Adapter Kit", can lead to uncomfortable "vibration" that you feel when you touch the top case, depending on the the hotel/airbnb. Whenever I visit I expect I should charge while I'm not using the device.

[anothernewdude]

In researching why it was happening to me, I found sufficient forum posts complaining about it that it seems to be commonplace.

I have my doubts that Apple would admit enough to perform a safety recall given the issues they've had with their garbage chargers in the past. Other companies have no problems with building hardware that lasts. Apple seem to prefer their customers pay for replacements.