a data processing system and method providing a jumper which provides standby power from a redundant power supply to one of at least two critical functions in a frame having bays for holding at least two nodes . the redundant power supply supplying power to one of the nodes in the frame and one of the critical functions . a jumper is slidably engageable in the frame in place of one of the nodes . the jumper , when engaged in the frame , transfers power from the redundant power supply to the other of the critical functions . the jumper is included in a jumper book of an airblock which includes passive airblock books . mechanical keys on the passive airblock books prevent the removal of the jumper book until after the passive airblock books are removed .