Part A
0451005.MRL
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 6135 PCS
- Package
- 2-SMD
- Series
- Fuses
Replacement verdict
Compatible functional replacement candidate
The 0451007.MRL and 0451005.MRL are both fast-acting surface-mount fuses from the same manufacturer series, sharing identical voltage ratings, interrupt ratings, and package footprints. The primary distinction is the current rating, which requires careful validation against the actual circuit load requirements before substitution.
Current Rating
Validation required
Voltage Rating
High match
Package Type
High match
Breaking Capacity
High match
Parts at a glance
Part B
0451007.MRL
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 4553 PCS
- Package
- 2-SMD
- 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 | 0451007.MRL | 0451005.MRL | Why it matters |
|---|---|---|---|
| Current Rating | 7 A | 5 A | Determines the maximum continuous current the fuse can carry without opening; a lower-rated fuse will open at lower overload currents. |
| Melting I²t (Nominal) | ~26.5 A²s | ~13.5 A²s | Represents the thermal energy required to open the fuse; affects how quickly it responds to overcurrent events and its pulse-withstanding capability. |
| Voltage Rating | 125 V AC / 125 V DC | 125 V AC / 125 V DC | Must meet or exceed the circuit voltage to ensure safe interruption of the fault current without restriking. |
| Interrupting Rating | 50 A @ 125 V AC / 300 A @ 125 V DC | 50 A @ 125 V AC / 300 A @ 125 V DC | Defines the maximum fault current the fuse can safely clear; must exceed the available short-circuit current of the application. |
| Fuse Type / Class | Fast-acting, surface-mount (Nano2) | Fast-acting, surface-mount (Nano2) | Determines the time-current response characteristic and physical mounting compatibility in the circuit. |
| Package / Size | Nano2 (2410 / 6.1 x 2.69 mm) | Nano2 (2410 / 6.1 x 2.69 mm) | Ensures the fuse physically fits the PCB footprint and holder; identical packages allow direct drop-in replacement. |
| Operating Temperature Range | -55 °C to +125 °C | -55 °C to +125 °C | Affects the fuse's current-carrying capacity due to temperature derating and confirms suitability for the application environment. |
| Approvals / Compliance | UL, CSA, RoHS | UL, CSA, RoHS | Certifications confirm the fuse meets recognized safety and environmental standards required for the end product. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0451005.MRL | 0451007.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 | 7 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 | 50A |
| Melting I²t | 5.566 | 10.32 |
| Approval Agency | CSA, PSE, UL | CSA, PSE, UL |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
Frequently asked questions
What are the 0451007.MRL and 0451005.MRL fuses?
The 0451007.MRL and 0451005.MRL are surface-mount fast-acting ceramic body fuses from Littelfuse's 451 series. The 0451007.MRL is rated 7 A and the 0451005.MRL is rated 5 A, both with a voltage rating of 125 V AC and 125 V DC.
What is the main difference between the 0451007.MRL and 0451005.MRL?
The primary difference is the current rating: the 0451007.MRL is rated for 7 A, while the 0451005.MRL is rated for 5 A. Both share the same 451 series platform, package size, voltage rating, and interrupting characteristics.
Are the 0451007.MRL and 0451005.MRL interchangeable?
No, they are not directly interchangeable because they have different current ratings. Substituting a 5 A fuse with a 7 A fuse (or vice versa) changes the overcurrent protection threshold and may violate the design's safety requirements. Replacement must be based on the circuit's specified current rating.
What is the physical package and mounting type of these fuses?
Both the 0451007.MRL and 0451005.MRL are surface-mount (SMD) fuses in a ceramic body with a 6.1 mm x 2.7 mm footprint (2410 case size). They are designed for automated PCB assembly and reflow soldering.
What are the voltage and interrupting ratings for these fuses?
Both fuses are rated 125 V AC and 125 V DC. The 0451007.MRL has a nominal interrupting rating of 50 A at 125 V AC/DC, and the 0451005.MRL also has a nominal interrupting rating of 50 A at 125 V AC/DC, as specified in the Littelfuse 451 series datasheet.
What is the operating temperature range for the 0451007.MRL and 0451005.MRL?
Both fuses are specified for an operating temperature range of -55 °C to +125 °C, with derating considerations applied according to the Littelfuse 451 series datasheet.
Do these fuses carry any recognized safety certifications?
Yes, the Littelfuse 451 series fuses, including the 0451007.MRL and 0451005.MRL, are recognized under UL 248-14 and certified to CSA C22.2 No. 248.14, as stated in the manufacturer's datasheet.
What are typical applications for the 0451007.MRL and 0451005.MRL?
These fuses are typically used for overcurrent protection in power supplies, battery packs, consumer electronics, and industrial control equipment where a compact surface-mount fast-acting fuse with a 125 V rating is required. The specific current rating (5 A or 7 A) must be selected based on the application's normal operating current and fault current profile.