What the 1.5 A rating and 50 A breaking capacity mean for your board
The 045101.5NRL is a 1.5 A fast-blow fuse in the NANO² 451 series, rated for 125 VAC and 125 VDC. The 50 A breaking capacity at rated voltage means it safely interrupts a fault current up to 50 A without rupturing the package or sustaining an arc — critical for clearing a hard short on a 125 V rail where the available fault current can exceed the fuse's own rating.
Melting I²t and cold resistance — sizing for inrush and voltage drop
With a melting I²t of 0.853 A²s, this fuse tolerates brief inrush pulses from capacitive or inductive loads without nuisance opening — a 10 ms pulse at 9 A draws roughly 0.81 A²s, leaving a small margin before the element reaches its melting point. The 0.063 ohm DC cold resistance at 25 °C produces a voltage drop of under 95 mV at rated current, negligible for a 125 V supply but worth checking if the load is a low-voltage rail downstream of a regulator.
Surface-mount package and temperature range
Housed in a 2-SMD square end block measuring 6.10 mm x 2.69 mm x 2.69 mm, the 045101.5NRL mounts directly to the PCB pad pattern typical for 2410-size chip fuses.
Compliance and approvals
Approved by CSA, PSE, and UL — the UL listing confirms the fuse meets the standard for branch-circuit protection in North American equipment, while PSE opens the Japanese market.