PSU: Corsair TX550M
Okay so, yes it is silly that I've turned it on again after the first spark. The first time it happened I thought it was the LED strip on my table, as it came from that direction and was the only electronic in that area. I naturally assumed my PC would definitely never spark like that. This also meant that I continued using it. The first spark caused the main circuit breaker in my house to trip. After the first spark I switched off the power strip, unplugged the LED (thinking it was that), and turned back on the breaker, power strip. I went to have dinner and my dad said he heard another pop, but this didnt shut off the breaker so I assumed it was not the same thing. I switched on the PC after dinner and it turned on fine and ran for a few minutes, before I shut it down again. I'm currently in the midst of building my new setup, having moved house, and hence I have been switching off the main power strip often while working on it. The next day I turn on the PSU switch, and everythings fine, until u click the power button. When I do, I hear the same pop as last time, catch a glimpse of a spark, the breaker trips again and I smell what you'd imagine burning *electronics* to smell like. Now I know it's my PC I'm like oh dear... and stupidly decide to turn it on again after resetting the breaker and properly plugging in everything again. I assumed it was a short on the (nonPC) side of the PSU, hence it was tripping my breaker. The spark also seemed like it'd be a short from the mains. This time, I didnt even have to press the on button. When I flicked the PSU switch, POP it went again and sparks. So I took it out of the PC and tested it on its own (attached video), and sure enough it made the same spark. This had me relieved that the short was within the PSU, but also kinda terrified if my pc is fried after all this.
I don't *think* my pc is dead, especially as it worked after the first spark. And because the spark was repeatable each time it was powered on, I believe a short had formed somewhere as opposed to me blowing an actual component within the PSU. Of course the breaker would trip before the spark could damage something else. Currently in the process of testing the PC with a new PSU, and will then RMA the original one.
What I am curious to know is, why or how could have this fault possibly developed? I am aware some products/components can simply prematurely fail, however especially with PSUs it's pretty rare, and most of the time it is as a result of something else. It was kept on a tabletop within the case and pretty clean, my system draws under 400w under intensive load, it has rarely been moved about and never physically damaged. Is it possible I did just get unlucky?
Testing the PSU externally: