Currently Being ModeratedFeb 20, 2013 4:11 PM (in response to Collett19)
Nothing to worry about. The iPad charger allows AC line voltage onto the shell of the iPad, but it is current-limited so you can't be hurt by it. It just feels funny, and I guess in certain circumstances it sounds funny.
Since the charger is not polarized, flip it around in the AC socket and the voltage on the shell may be lower (or higher, depending on how you have it now) so you may notice a difference one way vs. the other. In any case, there is no danger to you nor harm to the iPad.
Currently Being ModeratedFeb 20, 2013 4:15 PM (in response to rockmyplimsoul)
Thats sounds like whats happening, Is there a reason for the current running into the shell?
Would give the flipping the adaptor a try but i'm in the UK and they only work one way.
Thank you for your help
Currently Being ModeratedFeb 20, 2013 4:29 PM (in response to Collett19)
AC/DC adapters come in different designs, and the higher current output of the iPad charger uses a different design than the iPhone (or iPad mini) charger. Most adapters these days are "switch-mode" design for better efficiency, but I suspect that the iPad charger may be a linear design, such that one tap of the transformer is tied to the ground lead of the dock cable, and thus the iPad shell.
You'd be shocked (pun intended) to know that the voltage on the iPad shell may be about half your line voltage ... it is about 40-50 VAC here in the US, or if you flip it around (since the US charger is not polarized) it may be only about 20-25 VAC. But as I said, the supply is current-limited, and is well within international safety limits.