Macbook air 45w Magsafe 2 charger, Please help!

I recently traveled to Dominican Republic, I was using my laptop and wanted to charge it. When plugging my charger (my charger is very old, and had some "fixes" with electrical tape) to a wall outlet ( the charger had its 3-prong extension on, because I left my 2 prong extension at home) I suddenly felt current coming out from the part that connects to the computer. Because I really needed my computer, I plugged it in and then the shock was felt all over the computer. I got scared, so I unplugged it and bought a new charger of 60w because I couldn't find a 45w one. It worked, since the charger had a 2 prong extension, it charged fine and the shocks were gone. Then I was sure that my previous old cable was the problem. But, I tried using the3 prong extension of the previous 45w charger with the newly 60w, but once I plugged it in I felt the shock again, at the end of the charger.

Therefore, is there a problem with my extension? or a problem with the current at the place I stay in ?

For any answer I'll appreciate it.