Part A
0451005.MRL
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 6135 PCS
- Package
- 2-SMD
- Series
- Fuses
Replacement verdict
Compatible functional replacement candidate
The 0451005.MRL and 0451010.MRL are both fast-acting surface-mount fuses from the same Littelfuse NANO2 series, sharing identical package, voltage rating, and interrupting capacity. The primary distinction is the current rating, making the 0451010.MRL a viable higher-current alternative only where the circuit's continuous current and fault protection requirements are re-evaluated accordingly.
Current Rating
Validation required
Package Type
High match
Voltage Rating
High match
Interrupting Rating
High match
Parts at a glance
Part B
0451010.MRL
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 7413 PCS
- Package
- SMD-2
- Series
- Fuses
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 | 0451010.MRL | Why it matters |
|---|---|---|---|
| Current Rating | 5 A | 10 A | Determines the maximum continuous current the fuse can carry without opening; a direct functional substitutability constraint. |
| Voltage Rating | 125 VAC / 125 VDC | 125 VAC / 125 VDC | Must meet or exceed the circuit voltage to ensure safe interruption of fault currents. |
| Interrupting Rating | 50 A at 125 VAC / 50 A at 125 VDC | 50 A at 125 VAC / 50 A at 125 VDC | Defines the maximum fault current the fuse can safely clear without rupturing or arcing. |
| Nominal Melting I²t | 26.5 A²s | 120 A²s | Indicates the energy required to open the fuse; affects coordination with downstream components and inrush withstand. |
| DC Cold Resistance | 0.0155 Ohm | 0.0075 Ohm | Lower resistance reduces voltage drop and power dissipation in normal operation. |
| Fuse Type | Fast-Acting (Nano2) | Fast-Acting (Nano2) | Fast-acting behavior is critical for protecting sensitive semiconductors from overcurrent events. |
| Package / Size | Nano2 SMF (6.1 mm x 2.69 mm) | Nano2 SMF (6.1 mm x 2.69 mm) | Physical footprint and mounting style must match the PCB layout for drop-in replacement. |
| Operating Temperature Range | -55°C to +125°C | -55°C to +125°C | Ensures reliable operation and proper derating across the application's thermal environment. |
| Approvals / Standards | UL Recognized, CSA Certified, PSE | UL Recognized, CSA Certified, PSE | Compliance with safety agency standards is required for end-product certification and market acceptance. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0451005.MRL | 0451010.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 | 10 A |
| Voltage Rating - AC | 125 V | 125 V |
| Voltage Rating - DC | 125 V | 125 V |
| Response Time | Fast Blow | Fast Blow |
| Breaking Capacity @ Rated Voltage | 50A | 35A AC, 50A DC |
| Melting I²t | 5.566 | 26.46 |
| Approval Agency | CSA, PSE, UL | CSA, PSE, UL |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
Frequently asked questions
What are the 0451005.MRL and 0451010.MRL fuses?
The 0451005.MRL and 0451010.MRL are surface-mount fast-acting ceramic body fuses from Littelfuse's 451 series. The 0451005.MRL is rated 5 A and the 0451010.MRL is rated 10 A, both with a voltage rating of 125 VAC/VDC and a breaking capacity of 50 A at 125 VAC/VDC.
What is the main difference between the 0451005.MRL and 0451010.MRL?
The primary difference is the current rating: the 0451005.MRL is rated for 5 A, while the 0451010.MRL is rated for 10 A. Both share the same 451 series platform, package size (6.1 mm x 2.69 mm x 2.69 mm), voltage rating (125 VAC/VDC), and interrupting rating (50 A).
Are the 0451005.MRL and 0451010.MRL interchangeable in a circuit?
No. They are not interchangeable because they have different current ratings (5 A vs. 10 A). Substituting one for the other can compromise overcurrent protection, cause nuisance opening, or fail to protect the circuit adequately. Always match the fuse rating to the design requirements.
What is the voltage rating and breaking capacity of these fuses?
Both the 0451005.MRL and 0451010.MRL have a voltage rating of 125 VAC/VDC and a breaking capacity (interrupting rating) of 50 A at 125 VAC/VDC. These ratings must not be exceeded in the application.
What is the operating temperature range for the 0451005.MRL and 0451010.MRL?
Both fuses are rated for operation from -55 °C to +125 °C, with derating required at elevated temperatures according to the manufacturer's temperature derating curve.
What package and mounting type do the 0451005.MRL and 0451010.MRL use?
Both are surface-mount (SMD) fuses in a ceramic body with a 6.1 mm x 2.69 mm x 2.69 mm footprint. They are supplied on tape and reel for automated assembly and are compatible with standard reflow soldering processes.
Do the 0451005.MRL and 0451010.MRL have the same time-current characteristics?
Yes. Both are fast-acting (F) fuses in the Littelfuse 451 series and share the same time-current characteristic curve family. However, the absolute melting I²t and opening times differ because the 0451010.MRL carries a higher current rating.
What certifications and compliance standards apply to these fuses?
The Littelfuse 451 series fuses, including the 0451005.MRL and 0451010.MRL, are recognized under UL 248-14 and certified to CSA C22.2 No. 248.14, and they are RoHS compliant and halogen-free per the manufacturer's published datasheet.