Arto Nupponen has a particularly interesting case, and I’ve reproduced his photos here with his permission. Arto had a Molex-SATA adapter where only the 5V rails were being used. As with all the others, this eventually started to burn up and melt the plastic housing. Arto was using a better quality PSU than the average consumer units, and so it possibly cut-out more quickly which could explain why this one hasn’t burned quite so badly as the others.
These adapters generally split a Molex power connector into two SATA power connectors. Arto even experienced some SATA connectors burning up when they weren’t connected to a device! Interestingly, his company were able to put some of the adapters into an x-ray machine, and here is what they look like:
It seems the copper somehow “grows” through the plastic and eventually shorts the conductors together. The cause may be impurities in the plastic, but I’m not really sure exactly how the process occurs.
Anyone have any comments on what might be happening here?