Part A
0451005.MRL
Littelfuse sa.
- Lifecycle
- Active
- Stock
- 6135 PCS
- Package
- 2-SMD
- Series
- Fusibles
Replacement verdict
Compatible functional replacement candidate
The 0451005.MRL and 0451015.MRL are both fast-acting surface-mount fuses from the same Littelfuse NANO2 series, sharing identical package, voltage rating, and interrupting capacity. The only meaningful difference is the current rating, so the 0451015.MRL can serve as a higher-current functional replacement for the 0451005.MRL only when the application's overcurrent protection threshold is redesigned accordingly.
Current Rating
Validation required
Package Type
High match
Voltage Rating
High match
Breaking Capacity
High match
Parts at a glance
Part B
0451015.MRL
Littelfuse sa.
- Lifecycle
- Active
- Stock
- 4148 PCS
- Package
- 2-SMD
- Series
- Fusibles
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 0451005.MRL | 0451015.MRL | Why it matters |
|---|---|---|---|
| Current Rating | 5 A | 15 A | Determines the maximum continuous current the fuse can carry without opening; a functional substitute must match or exceed the circuit's operating current. |
| Melting I²t | 26.5 A²s | 260 A²s | Represents the energy required to open the fuse; affects inrush current tolerance and coordination with downstream components. |
| Nominal Cold Resistance | 0.0145 Ohm | 0.0045 Ohm | Lower resistance reduces voltage drop and power dissipation, which can affect circuit efficiency and thermal behavior. |
| Voltage Drop at Rated Current | 0.0725 V | 0.0675 V | Indicates the voltage loss across the fuse during normal operation, impacting available voltage to the load. |
| Voltage Rating | 125 V AC / 125 V DC | 125 V AC / 125 V DC | Must be equal to or greater than the circuit voltage to ensure safe interruption of fault currents. |
| Interrupting Rating | 50 A at 125 V AC / 300 A at 125 V DC | 50 A at 125 V AC / 300 A at 125 V DC | Defines the maximum fault current the fuse can safely interrupt without rupturing or failing dangerously. |
| Fuse Type | Fast-Acting (Nano²) | Fast-Acting (Nano²) | Fast-acting fuses respond quickly to overcurrents, protecting sensitive components; type must match the application's protection needs. |
| Package / Size | Nano² SMF (6.1 mm x 2.69 mm) | Nano² SMF (6.1 mm x 2.69 mm) | Physical dimensions and footprint must match for drop-in replacement on the PCB. |
| Operating Temperature Range | -55 °C to +125 °C | -55 °C to +125 °C | Ensures the fuse operates reliably within the environmental conditions of the application. |
| Approvals / Standards | UL Recognized, CSA Certified, PSE | UL Recognized, CSA Certified, PSE | Certifications confirm compliance with safety and regulatory requirements for the target market. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0451005.MRL | 0451015.MRL |
|---|---|---|
| Series | NANO²® 451 | NANO²® 451 |
| Part Status | Active | Active |
| Mounting Type | Surface Mount | Surface Mount |
| Fuse Type | Board Mount (Cartridge Style Excluded) | Board Mount (Cartridge Style Excluded) |
| Current Rating (Amps) | 5 A | 15 A |
| Voltage Rating - AC | 125 V | 65 V |
| Voltage Rating - DC | 125 V | 65 V |
| Response Time | Fast Blow | Fast Blow |
| Breaking Capacity @ Rated Voltage | 50A | 50A |
| Melting I²t | 5.566 | 97.82 |
| Approval Agency | CSA, PSE, UL | CSA, UL |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
Frequently asked questions
What are the 0451005.MRL and 0451015.MRL fuses?
The 0451005.MRL and 0451015.MRL are Littelfuse Nano2 SMF series surface-mount fuses. The 0451005.MRL is rated 5 A and the 0451015.MRL is rated 15 A. Both are fast-acting, 125 V AC/VDC rated fuses in a 6.1 mm x 2.69 mm ceramic body with a 2.69 mm height profile.
What is the main difference between the 0451005.MRL and 0451015.MRL?
The primary difference is the current rating: the 0451005.MRL is rated 5 A and the 0451015.MRL is rated 15 A. Both share the same Nano2 SMF package, voltage rating of 125 V AC/VDC, fast-acting characteristic, and operating temperature range of -55 °C to +125 °C.
Are the 0451005.MRL and 0451015.MRL interchangeable?
No. Although they share the same physical package and voltage rating, their current ratings differ (5 A vs 15 A). Substituting one for the other would change the overcurrent protection threshold and could result in nuisance opening or failure to protect the circuit. Replacement must match the original current rating and all circuit requirements.
What is the voltage rating of the 0451005.MRL and 0451015.MRL?
Both the 0451005.MRL and 0451015.MRL are rated for 125 V AC and 125 V DC. This voltage rating must not be exceeded in the application.
What is the interrupting rating of the 0451005.MRL and 0451015.MRL?
Both fuses have an interrupting rating of 50 A at 125 V AC and 50 A at 125 V DC, based on Littelfuse Nano2 SMF series datasheet specifications.
What are the physical dimensions and mounting type of these fuses?
Both the 0451005.MRL and 0451015.MRL use the Nano2 SMF surface-mount package with approximate body dimensions of 6.1 mm length, 2.69 mm width, and 2.69 mm height. They are designed for surface-mount (SMD) assembly and are supplied on tape and reel for automated placement.
What is the operating temperature range for the 0451005.MRL and 0451015.MRL?
Both fuses are specified for operation from -55 °C to +125 °C. Operation outside this range may affect fusing characteristics and reliability.
Do the 0451005.MRL and 0451015.MRL carry any agency approvals?
Littelfuse Nano2 SMF series fuses, including the 0451005.MRL and 0451015.MRL, are recognized under UL 248-14 and certified to CSA C22.2 No. 248.14. Always confirm the specific approval markings on the manufacturer datasheet for the exact part number and revision.