An embodiment of the present invention discloses a technique that allows hot plugging a peripheral controller card, containing both a local bus and a peripheral bus on a single connector, into a host system board containing a host system bus and a host I/O bus. When mating the peripheral controller card to the host system board a local device power supply (LDPS) is inactive, a peripheral device power bus (PDPB) is powered, and signal lines of a peripheral device are maintained in a high impedance state. Following a delay after the mating, the LDPS is activated by the host operating system (OS). Following the activation of the LDPS, the host system bus is coupled to the single connector through switches that are under OS control. In response to the activation of the LDPS, the signal lines of the peripheral device are enabled.In a disclosed embodiment the peripheral controller card is a disk array controller card, the local bus is a PCI bus, and the peripheral bus is a SCSI bus. In one embodiment the disk array controller card is coupled to a mass storage peripheral and in another embodiment is programmed for RAID. An advantage of an embodiment of the present invention is that a PCI bus and a SCSI bus are carried on a single peripheral connector which provides cable management and readily allows hot plugging a redundant peripheral controller card into the host system board.