Wow. I had never experienced this until I moved from US to NL. It sometimes really bothers (scares?) me. If you have two Macbooks side by side, and you touch them both at the same time, you can get an even bigger sensation.

Now since you're in this area of expertise, do you think it's possible that on rare occasions I could lightly stroke another human (let's say in a bed, on a waterbed (water filled rubber container)) and feel the same sensation as I feel sometimes when I stroke the computer? Could be that both turn me on, but I'm pretty sure this was not imagined. It was also rare and strong when it happened.

The sensation comes from the Macbook case voltage differing from that of ground, and finding a path to ground through your body. Sometimes, when you feel the sensation coming from the computer, if you lift your feet off the ground the sensation stops. This is because you are no longer a path to ground.

It's totally possible for this path to ground to go through two humans, making it feel like their skin is buzzing! For example, if your friend is in bed using a Macbook, they're insulated from ground and thus at Macbook case voltage. If you stand on the ground beside them and touch them, the current now finds a path to ground through both your bodies!

> until I moved from US to NL

So, my guess is you're using the 2 pronged brick (US) plug with a US->EU plug adaptor.

It also happens with EU spec machines and their respective EU power supplies. Could be that some of these older homes aren't properly grounding some outlets, so regardless of what you stick in there, maybe you're not getting a ground.

Despite how dangerous it sounds, I've never heard of anyone having a real shock... so I guess it's fine.

Hi, could you explain why this happens normally? Isn't the output neutral line of the DC charger supposed to be pretty much 0/ground anyway? Or is it that the neutral is a few volts off the ground?

I wish I could, but I honestly don't know. All I know for sure is that using the ground pin 100% fixes it. If anybody on here could explain it, I'd be super grateful!

There are filtering capacitors between mains and ground, see https://www.edaboard.com/threads/capacitors-between-power-an...

This happens to me when I use my MacBook on a bed with an electric blanket

I think this actually will succeed

I was looking for it for ages. Please make a British version as well! This is neat!

Glad you like it! But I thought the UK duckhead already has a ground pin?

https://www.apple.com/uk/shop/product/MKU63B/A/67w-usb-c-pow...

At least on my older mag safe charger, only 2 pins are connected. You can pull off the UK plug and plug in the US or EU one, or even just a regular figure 8 lead (not sure of the correct name for these!)

Had a few times where I've had to disconnect the charger as I could feel an effect like static electricity on the metal case of the MacBook.

Oh wow! Sure enough, the UK adapter _has_ the ground pin, but it's not connected to anything .

https://apple.stackexchange.com/questions/17575/how-to-prope...

Alright if I sell any of this North American grounded version, I'll make one for y'all across the pond!

That's right, but the short version isn't connected to the ground. https://discussions.apple.com/thread/8594979

I just found this too. So strange to have a useless prong--maybe it's just for mechanical support? IMO if thats the case they should make the whole prong plastic to indicate its lack of electrical function.

That's actually useful.