At 4-5 years old, on a unit that has a five year warranty, it's getting to the age where anything is possible however aside from being group regulated, which isn't really a major issue on your platform as it might be on some others, it's decent. It was a fairly good unit back when it was new, but the platform is pretty outdated now and group regulated units are discouraged on modern hardware when purchasing new, especially on enthusiast or gaming type systems.
I would think that if you had no issues with that unit, even recently, at other locations, the problem is likely due to the wiring or breaker at this location, but obviously when you move something from one location to another (Or even when you don't) anything is possible. Stuff gets bumped or dropped or dinged and things can break or be damaged sometimes even from very light rough treatment. Even just enough vibration can cause delicate parts to become disagreeable. LOL.
So, my thought is, take it to a different location. Somebody else's house, or work, or a family member, and see if there is any problem with it there. If not, then you know it's the house not the system. IF it does still have an issue, then it is time to start troubleshooting and the PSU might actually not be a bad thing to simply replace as a matter of course if that becomes the case.