i plug direct to the mains and i feel a zap occasionally on my palms and hands when i type. i use bodyguardz so i get zapped at those small tiny exposed edges around the palm rest area. at first i thought , ok maybe it was the earthing cable not doing the job right. so i removed the power adapter and tried to work on battery source, i still got zapped. u know those screw drivers electricians use to test for electricity? this small light bulb within will light up when there is electricity present.. so i took one of those screw drivers, touch at some areas and the light goes up. i touched at the corners of the palm rest, keyboard, i remind u, power adapter was removed and i work on a wooden table. still on my 1 year warranty.. applecare would listen right? btw, those moisture sensors where can i find them?