Power cord plug in overheated, black smoke and extremely hot...

Question

My daughter has had the Macbook for less than a year. She says it has always sparked when plugging in/out but tonight
black smoke started coming out of the box where the prongs are. I am extremely upset...this could have caused a fire.
I understand we can probably get a new one as it's under warranty, my concern is still the fact that it overheated in the
first place.
We do not have an Apple store in our small town and she needs a replacement asap. Should I just call the support
helpline? I'd like to think they'd take this seriously...
Here's a photo..the prong where it's burned was extremely hot, the other prong cool. ://

Answer 1

Except that it is normal under many circumstances.
Any capacitive load on a circuit will tend to resist changes in voltage, with the result that plugging in a capacitive load will often cause a small spark to form.  Similarly, an inductive load will tend to resist changes in current, which is why unplugging a running electric motor will also often cause a small spark to form.  The transformer in a power adaptor, when connected at the other end, is a capacitive load.
The trick, of course, is being able to differentiate between these effects and sparks caused by short-circuits in the socket or plug, which can be extremely dangerous fire hazards.  Certainly if there are other indicators of a short-circuit, like heat being generated, then it must be checked out.  In fact, if there's any uncertainty, it should probably be checked out.
However, explaining that there can be sparks in a perfectly functioning socket is not the same as telling people that sparking can, or should, be ignored.  If anything, it's telling them not to ignore it, but to investigate it.