800 mA fast-blow SMD fuse for secondary-side protection
The Littelfuse 0451.800NRL is an 800 mA fast-blow surface-mount fuse from the NANO²® 451 series, rated for 125 V AC and 125 V DC with a breaking capacity of 50 A at rated voltage. The 0.271 melting I²t value lets you coordinate this fuse with downstream traces and semiconductor ratings — the energy let-through is low enough to protect a 125 V rail feeding a DC-DC converter or a control transformer secondary. Approved under CSA and UL, so it passes the panel-level certification for industrial control equipment and power supplies shipped into North America.
Package, footprint, and storage note
Housed in a 2-SMD square end block measuring 6.10 mm x 2.69 mm x 2.69 mm — the same footprint as the rest of the NANO² 451 family, so a single pad layout serves multiple current ratings on the same BOM.