Not sure where to post this question. Does anyone know what the third wire is for on a brushless fan?
Is it based upon how much ground is apply to the third wire?
If you don't need fancy fan control just cover the bare end with heat shrink tubing and leave it alone.
On something like a server farm, you can not expect people to keep a close eye on things real time not practical. For a CB or ham operator, it is possible to expect smart operation but it is easier to plan for an idiot and build accordingly.