2 A fast-blow SMD fuse — what the ratings mean for fit
The 0451002.NR: Rated 2 A continuous at both 125 VAC and 125 VDC. The fast-blow response time means it clears quickly on overcurrent — no intentional delay for inrush. The 50 A breaking capacity at rated voltage tells you it can safely interrupt a fault current up to that level without rupturing; this is the figure that governs whether the fuse clears a short-circuit event in your circuit without cascading damage. Melting I²t is 0.53 — this is the energy needed to melt the fuse element. It matters for sizing the fuse against inrush pulses: if your load's surge energy exceeds this value, the fuse will open on turn-on. The DC cold resistance is 0.0367 Ohms, so the voltage drop at 2 A is about 73 mV — negligible in most low-voltage rails.
Housed in a 2-SMD square end block package with dimensions 6.10 mm x 2.69 mm x 2.69 mm. Surface-mount, supplied on Tape & Reel.
Approvals and temperature range
Approved by CSA, PSE, and UL — accepted in North American and Japanese regulatory jurisdictions.