I have a mining rig with 8 GTX 1060 3GB connected via risers, the risers are connected via SATA power connectors to Corsair HX850. When the rig stopped working I noticed that one SATA connector on the PSU is molten:
I made the rig work by replacing the cable and risers with new ones but did not figure out what exactly caused this. Also it is not clear is there a limitation on how many risers can be connected to the same SATA cable. Originally there were 6 risers on this cable, now there are 4 or 2.
Before that there was some molten cable on some other KCASS PSU that was found to be faulty by the vendor:
so in this case I got the money back.