I confess to being a bit baffled at how these power cord defects keep happening. Your basic AC power cord is ancient by the standards of electronic gizmos and by far the simplest thing going into a modern laptop.
recently we had a power cord melt and nearly start a fire in our server room while power maintenance was occurring (so power was only going to 1 PSU instead of both PSUs). Turns out the cables don't meet the appropriate standards (IEC 60950) despite being stamped with "10A".
The cross-section of the copper strands in the failed cable was smaller than that of a 'proper' cable. These cables were illegal, but are being imported from cheap manufacturers in China (obviously without testing to Western standards) and being sold at somewhat reputable stores. Beware of cables marked "PVC YOUZHI DIANXIAN 3x0.75mm2"