SPXC Solar Fuses Littelfuse SPXC Solar Fuses feature a 1500VDC voltage rating and 1A to 4A current range in a 10mm x 57mm package. SPXC fuses help to eliminate common low-overload faults and provide an interrupting rating up to 50,000A. The SPXC-S series is a solar string fuse that is silver plated. Littelfuse SPXC Solar Fuses are ideally suited for use in inverters and combiner boxes.