I have been tormenting myself with the owners manual:
POWER INPUT – VOLTAGE SELECTOR SWITCH - The SHUTTLE 6.0® utilizes rear panel switch selectable universal power supply that operates from 100V to 240 volts, 50 to 60 Hz for world wide use. Simply set the switch to the appropriate AC mains voltage (BEFORE connecting to the power source), and utilize the proper IEC cord-set appropriate for the country the product is being used.
For countries using 100V, 110V, 115V and 120V AC mains, select the 115V switch position on the Voltage Selector switch.
For countries using 220V, 230V, and 240V AC mains, select the 230V switch position on the Voltage Selector switch.
There is no externally accessible AC mains (line) fuse, the internal fuse is integral to the SMPS power supply and is not user serviceable. This fuse will not fail except under very unlikely fault conditions to the SMPS, and if this occurs a qualified service technician is required to correct the problem.