Littelfuse 0251.250NRT2 Board Mount Fuse – Equivalent & Substitute Parts

Part Overview

The Littelfuse 0251.250NRT2 is a 250 mA, 125 V AC/DC board mount axial fuse from the PICO® II 251 series. This part is classified as obsolete. Due to its obsolete status, equivalent substitute parts with active product status are available to ensure design continuity and supply chain reliability. All substitutes maintain identical electrical and mechanical specifications while offering improved availability and compliance certifications.

Key Parameters

Parameter	Value
Current Rating	250 mA
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Through Hole
Package / Case	Axial
Size / Dimension	0.110" Dia x 0.280" L (2.80mm x 7.11mm)
Breaking Capacity @ Rated Voltage	50A AC, 300A DC
DC Cold Resistance	0.665 Ohms
Melting I²t	0.0116
Operating Temperature Range	-55°C ~ 125°C
Approval Agencies	CSA, cURus

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters:

Current Rating: 250 mA (exact match required)
Voltage Rating: 125 V AC and 125 V DC (exact match required)
Response Time: Fast Blow (exact match required)
Mounting Type: Through Hole (exact match required)
Package / Case: Axial (exact match required)
Physical Dimensions: 0.110" Dia x 0.280" L (exact match required)
Electrical Performance: Breaking Capacity, DC Cold Resistance, and Melting I²t (exact match required)
Approval Agencies: CSA and cURus certification (required for all substitutes)

All substitute parts listed below meet these criteria and are classified as active products with improved RoHS3 compliance status compared to the obsolete original part.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating	Voltage (AC/DC)	Response Time	Package	Dimensions	Breaking Capacity	DC Resistance	Melting I²t	Product Status	RoHS Status	Packaging Type
0251.250NRT2	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Obsolete	RoHS Non-Compliant	—
0251.250MXL	Littelfuse	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Bulk
0251.250HAT1L	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Cut Tape (CT)
0251.250MAT1L	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Cut Tape (CT)
0251.250MRT1L	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Cut Tape (CT)
0251.250NAT1L	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Cut Tape (CT)
0251.250NRT1L	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Cut Tape (CT)
0251.250PARL	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Tape & Reel (TR)
0251.250PF001L	Littelfuse Inc.	PICO® II 251	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC, 300A DC	0.665 Ω	0.0116	Active	ROHS3 Compliant	Tape & Reel (TR)
0491.250MAT1	Littelfuse	PICO® II 491	250 mA	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	50A AC	0.665 Ω	—	Active	ROHS3 Compliant	Cut Tape (CT)
7010.7030.13	SCHURTER Inc.	172322	250 mA	125 V / 125 V	Fast Blow	Cartridge, Non-Standard (Axial)	0.093" x 0.315"	300A DC	—	0.0094	Active	ROHS3 Compliant	Bulk

Engineering Selection Recommendations

Primary Substitutes (Littelfuse PICO® II 251 Series)

The following parts are direct electrical and mechanical equivalents with active product status and ROHS3 compliance:

0251.250MXL (Bulk packaging): Recommended for high-volume procurement and direct board mount applications.
0251.250NRT1L (Cut Tape): Highest inventory availability (112,295 pcs). Suitable for standard production runs.
0251.250MAT1L (Cut Tape): High inventory (3,595 pcs). Suitable for standard production runs.
0251.250NAT1L (Cut Tape): High inventory (10,807 pcs). REACH Affected status noted.
0251.250HAT1L (Cut Tape): Suitable for standard production runs.
0251.250PARL (Tape & Reel): Recommended for automated assembly processes.
0251.250PF001L (Tape & Reel): Recommended for automated assembly processes.

Alternative Series Substitute (Littelfuse PICO® II 491)

0491.250MAT1 (Cut Tape): Equivalent electrical performance. Different series designation. Breaking Capacity rated at 50A AC only (DC rating not specified). Suitable where DC breaking capacity specification is not critical.

Cross-Manufacturer Substitute (SCHURTER)

7010.7030.13 (Bulk): Functionally equivalent 250 mA, 125 V AC/DC fuse. Physical dimensions differ (0.093" Dia x 0.315" L vs. 0.110" Dia x 0.280" L). Cartridge form factor differs from standard axial. Melting I²t lower (0.0094 vs. 0.0116). Operating temperature range narrower (-55°C ~ 85°C vs. -55°C ~ 125°C). Suitable only where mechanical envelope and thermal range differences are acceptable.

Frequently Asked Questions (FAQ)

Q: Can I use 0251.250NRT1L as a direct replacement for 0251.250NRT2?

A: Yes. Both parts are identical in electrical and mechanical specifications. The primary difference is product status: 0251.250NRT2 is obsolete, while 0251.250NRT1L is active with ROHS3 compliance. All electrical parameters, dimensions, and certifications are equivalent.

Q: What is the difference between Cut Tape (CT), Tape & Reel (TR), and Bulk packaging?

A: Packaging affects procurement and assembly processes. Cut Tape is suitable for manual or semi-automated assembly. Tape & Reel is optimized for fully automated pick-and-place assembly. Bulk packaging is used for high-volume direct procurement. Electrical and mechanical specifications are identical across all packaging types.

Q: Can I substitute the SCHURTER 7010.7030.13 for the Littelfuse 0251.250NRT2?

A: Electrical substitution is possible (250 mA, 125 V AC/DC, Fast Blow). However, mechanical differences exist: the SCHURTER part has different physical dimensions (0.093" Dia x 0.315" L) and a cartridge form factor. Operating temperature range is also narrower (-55°C ~ 85°C vs. -55°C ~ 125°C). Substitution is only valid if your design accommodates these mechanical and thermal differences.

Q: Why is 0251.250NAT1L marked as REACH Affected?

A: REACH Affected status indicates the part contains substances of concern under EU REACH regulations. This does not affect electrical or mechanical performance. Selection depends on regulatory requirements for your end application and geographic market.

Q: Which substitute offers the best availability?

A: 0251.250NRT1L has the highest inventory (112,295 pcs), followed by 0251.250NAT1L (10,807 pcs) and 0251.250MAT1L (3,595 pcs). Availability should be confirmed with your supplier for current stock levels.

Q: Are all substitutes CSA and cURus certified?

A: Yes. All Littelfuse PICO® II 251 and 491 series substitutes carry CSA and cURus certifications. The SCHURTER 7010.7030.13 carries CSA and UR certifications. All parts meet the required approval agency standards for this application category.

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