The current deratings are down to 5.5A for 12-circuit wire-to-board applications: https://www.molex.com/pdm_docs/ps/PS-43045-001.pdf https://www.molex.com/pdm_

The current deratings are down to 5.5A for 12-circuit wire-to-board applications: https://www.molex.com/pdm_docs/ps/PS-43045-001.pdf https://www.molex.com/pdm_docs/ps/PS-43045-001.pdf But that is allowing a maximum temperature rise of 30C, it uses 18AWG wire as you say, and it's supposed to be capable of 600V AC/DC; it's not supposed to decompose/leak more than 5mA when exposed to 2200V. All of that is overkill for inside of a PC. If you're willing to limit the operating voltage to 12V and can guarantee that your board side conductors have big, multi-plane copper traces pulling heat out of the contacts to an actively cooled heat sink, you can get away with a lot that you couldn't if you were using the connector as, say, an in-line disconnect in some conduit for a 480V servo drive.