Consult the Appendix E of the Fusion User Guide for instructions on changing the fuse cartridge for different operating supply voltage.
Please be aware that only the fuse for the initial territory the Fusion unit was sold into is included. Different fuses are required for 115V or 230V setting - DO NOT simply use the same fuse. Early Fusion units were sold with a link plate on one side of the fuse cartridge; both existing fuse and link plate should be replaced with two new fuses of the correct rating.
For 115V: 2 x 1A fuses are required
For 230V: 2 x 500mA (0.5A) fuses are required.