I have iMac mid 2011 although working perfect but i get the shock everytime I touch the key board or the body of imac. I got my wires checked & electrician declred them good. I tested with a tester & it gives out the light that current is leaking. My macbook pro 2017 also gives me shock. I think its something to do with 220V current countries (as it doesn't happens in US) but Apple should address this issue once for all. Apple's consumers live in every part of the world !