So I brought a new xbox one back from US to Denmark and realized (the hard way, aka smokey) that it is not usable on the 230V outputs.
xbox support has been helpful and I can buy a new 230V through them for 32.9 EUR plus 5.0 EUR shipping.
While I wait for that one I'm looking at how to power the xbox one using a PC (ATX) power supply. A lot of guides exists for the xbox 360 online, but I wasn't able to find the pinout of the xbox one power supply. So I simply took the damaged power supply apart and mapped out the pins:
Type Color Rating Note
GND Black/Grey - GND_5V is grey, but internally connected to GND.
12V Yellow 17.9 A
5V Red 1.0 A
PWRON Blue - Must be used for communication between xbox and PSU.
Follow any xbox 360 ATX power supply guide (like this: http://www.xpgamesaves.com/topic/21589-tutorial-xbox360-power-supply-mod-pc-psu/) but remember to use the PWRON pin to enable communication between the xbox one and the power supply.
Also note that the power supply in use must be able to deliver 17.9A at 12V (yellow wires) and 1A at 5V (red wire).