UNINTERRUPTIBLE POWER SUPPLY

An uninterruptible power supply according to this invention includes an uninterruptible-power-supply module including a power conversion housing accommodating a power converter. The uninterruptible power supply includes a bus part arranged outside the power conversion housing of the uninterruptible-power-supply module, and configured to deliver input/output power from/to the uninterruptible-power-supply modules. Also, the uninterruptible power supply includes a module interrupter provided between the uninterruptible-power-supply module and the bus part and configured to electrically entirely disconnect the uninterruptible-power-supply module from the bus part. Also, the uninterruptible power supply includes a bypass circuit part including a switching circuit for switching electrical conduction, and configured to supply AC power from a bypass AC power supply to the load without connection through the uninterruptible-power-supply module.