Ok, changed the charger now. I'll let you know if this fixes it.
Sparking is not good, at best its straining the charger. I have seen this with laptops if you plugin the charger when its connected to the laptop but generally not if its disconnected. if that's not the case there might be a circuit problem at that location. Even with a cheap charger its too coincidental that it would fail plugging into the same circuit... you sure that circuit is the correct voltage...Well, spoke too soon. Had an issue with an extension plug at work which was the plug that I first noticed it not charging on...then the problem got worse after 6 months to any plug...wondering if the extension is the problem, always sparks when i plug it in.