Hello evyone,
a my-2-cent-post:
when up on a tower, after a lightning strike, when you feel lucky that overvoltage damage only the PoE part of power supply into a RB, and with the power supply plugged on the RB female jack your RB is up & running, there’s a easy way to re-split power from your ethernet cable instead to cut out the blue and brown pairs from inside the cable to take it out for a male power connector.
Just take a Groove PoE injector, and substitute the female power jack with male power jack. Your original ethernet cable remain ready for new RB installation, and you just re-used a PoE grabbed from some dead groove 
That’s reverse PoE
Too obvious ? I agree, but sometime the most commonplace questions have the hardest answers.
Regards,
Cristiano aka [crt] - ROS/MK user since 2006.