Arc "fan controller" has me wondering

[Nurf]

The arc mini/midi r2 fan controller is a 5/7/12v switch. It atleast looks like its just a molex cable that's been made into 5, 7 and 12 volt connections on the switch's PCB. Fractal says there is one channel and that channel cannot exceed 15 watts.
First of all, I don't understand this limit. Why exactly does something that just rearranges the wires have such a low limit? What exactly will break if this limit is crossed?
Secondly, having to do with the first question, if the channel is overloaded what will actually happen if anything? Will it slowly heat up and break or will there suddenly come a point where it just says pop?

Is there someone in this forum that could educate me?

 

[mehere]

it maybe due to the current carrying limit on the pcb tracks and if so they may overheat/burn
had a molex to 7v fan adapter melt the cable once when I used it to power a 18w pump

 

[dalewakelin]

It will get hot, i wouldn't go more than 20w personally.

 

[Nurf]

My fans will in total be only a few watts over 15 (@12v) so I'm not worried, but I do find it interesting that the official limit is so low and wanted to hear you guys out instead of intentionally breaking it to find the answers.

 

[mehere]

if your under volting them you should be fine
as you get a 2 fold power drop as you drop volts because of the current drops as well
that is 50% voltage drop gives 75% power drop

 

[Nurf]

Thats true and I won't be keeping the fans on 12v unless I'm testing overclocks or benchmarking. Guess I'll just keep a finger on the pcb when I do have it at 12v

 

[mehere]

Thats true and I won't be keeping the fans on 12v unless I'm testing overclocks or benchmarking. Guess I'll just keep a finger on the pcb when I do have it at 12v

made me laugh
image in mind of burn pcb smoldering finger and saying o flip that didnt work

 

[Nurf]

It would probably be more like:
"Why aren't the fans working?"
5 minutes pass,
"whats that burnt smell?"
10 minutes pass,
"WTF happened to my finger"