Charger blew up

I have a Dell Latitude 5401. Troubles arrived the second day of use. The laptop overheats continuously and eventually switches off loosing the work that I am doing at that moment. After many attempts with Dell service, I finally got them to have a look to the laptop. They changed some pieces and now keeps overheating but at least I don't loose the work. The second big problem is that I just bought the 5th charger because the previous 4 ones all blew up. Doesn't matter the brand, because the two first were Dell original chargers and they exploded the same. Also, it's not connected with the electric system of the building because they exploded in different places (at work, at home, at my parents...). Can dell give me some explanation or solution?