The power supply backplane carries 12V power from the power supplies to the power distribution board over a pair of bus bars.
Note - Sun SPARC Enterprise T5140 servers do not use a power supply backplane. In these systems, the power supplies connect directly to the power distribution board.
Caution - The system supplies standby power to the power supply backplane even when the server is powered off. To avoid personal injury or damage to the server, you must disconnect the power cords before servicing the power supply backplane.