Littelfuse 0251002.NRT1 Equivalent & Substitute Parts

Part Overview

The Littelfuse 0251002.NRT1 is a 2 A, 125 V AC/DC axial board mount fuse from the PICO® II 251 series. This component is classified as obsolete, which necessitates identification of active equivalent parts for ongoing design support and procurement. The part maintains fast-blow response characteristics with a 50 A AC / 300 A DC breaking capacity, suitable for circuit protection in through-hole applications. Equivalent substitute parts are available within the same series with identical electrical and mechanical specifications but in active product status with improved RoHS compliance.

Key Parameters

Parameter	Value
Current Rating	2 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)
Package / Case	Axial
Breaking Capacity (AC)	50 A
Breaking Capacity (DC)	300 A
Melting I²t	0.405
DC Cold Resistance	0.0473 Ohms
Operating Temperature Range	-55°C to 125°C
Size / Dimension	0.110" Dia x 0.280" L (2.80mm x 7.11mm)
Approval Agencies	CCC, CSA, cURus, PSE, TUV

Substitute Part Grouping Explanation

Substitution of the obsolete 0251002.NRT1 is determined by strict equivalence across the following critical parameters:

Current Rating: 2 A (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)
Fuse Type: Board Mount, Axial configuration (exact match required)
Breaking Capacity: 50 A AC / 300 A DC (exact match required)
Melting I²t: 0.405 (exact match required)
DC Cold Resistance: 0.0473 Ohms (exact match required)
Operating Temperature: -55°C to 125°C (exact match required)
Physical Dimensions: 0.110" Dia x 0.280" L (exact match required)
Approval Certifications: CCC, CSA, cURus, PSE, TUV (exact match required)

All substitute parts listed below meet these criteria. Differences exist only in packaging format (Cut Tape, Tape & Reel, Tape & Box) and product status (all substitutes are Active vs. Obsolete for the main part). RoHS compliance status differs: the main part is RoHS non-compliant, while all substitutes are ROHS3 compliant.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating	Voltage AC/DC	Response Time	Breaking Capacity (AC/DC)	Melting I²t	DC Cold Resistance	Operating Temp	Dimensions	Packaging	Product Status	RoHS Status
0251002.NRT1	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Bulk	Obsolete	RoHS non-compliant
0251002.HAT1L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Cut Tape (CT)	Active	ROHS3 Compliant
0251002.MAT1L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Cut Tape (CT)	Active	ROHS3 Compliant
0251002.MRT1L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Cut Tape (CT)	Active	ROHS3 Compliant
0251002.NAT1L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Cut Tape (CT)	Active	ROHS3 Compliant
0251002.NRT1L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Cut Tape (CT)	Active	ROHS3 Compliant
0251002.PARL	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Tape & Reel (TR)	Active	ROHS3 Compliant
0251002.PAT1L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Tape & Box (TB)	Active	ROHS3 Compliant
0251002.PF001L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Tape & Reel (TR)	Active	ROHS3 Compliant
0251002.PF002L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Tape & Reel (TR)	Active	ROHS3 Compliant
0251002.PF006L	Littelfuse Inc.	PICO® II 251	2 A	125 V / 125 V	Fast Blow	50 A / 300 A	0.405	0.0473 Ω	-55°C ~ 125°C	0.110" Dia x 0.280" L	Tape & Reel (TR)	Active	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts are direct parametric equivalents to the obsolete 0251002.NRT1. Selection among these alternatives is determined by packaging and procurement requirements rather than electrical or mechanical performance differences.

For high-volume automated assembly operations, Tape & Reel packaging (0251002.PARL, 0251002.PF001L, 0251002.PF002L, 0251002.PF006L) is recommended. The 0251002.NRT1L variant offers the highest inventory availability (104,745 units) in Cut Tape format, suitable for moderate-volume pick-and-place operations.

For manual assembly or low-volume applications, Cut Tape variants (0251002.HAT1L, 0251002.MAT1L, 0251002.MRT1L, 0251002.NAT1L, 0251002.NRT1L) provide flexibility. The 0251002.PAT1L in Tape & Box packaging accommodates mixed-volume requirements.

All substitute parts carry identical regulatory certifications (CCC, CSA, cURus, PSE, TUV) and operate across the full -55°C to 125°C temperature range. The transition from RoHS non-compliant to ROHS3 compliant status across all substitutes aligns with current environmental and regulatory standards.

Frequently Asked Questions (FAQ)

Q: Can I directly replace 0251002.NRT1 with any of the listed substitutes in my circuit?

A: Yes. All substitute parts are parametric equivalents with identical electrical ratings (2 A, 125 V AC/DC), response characteristics (Fast Blow), breaking capacity (50 A AC / 300 A DC), and physical dimensions (0.110" Dia x 0.280" L). They are mechanically and electrically interchangeable at the board level.

Q: What is the difference between the packaging options?

A: Packaging differences affect procurement and assembly logistics only. Cut Tape (CT) is suitable for manual or semi-automated pick-and-place. Tape & Reel (TR) is optimized for high-speed automated assembly equipment. Tape & Box (TB) provides intermediate flexibility. All formats contain identical fuse elements with the same electrical performance.

Q: Why is the main part 0251002.NRT1 marked as obsolete?

A: Obsolescence indicates the part is no longer manufactured. The listed substitutes are active production parts from the same PICO® II 251 series with identical specifications, ensuring design continuity and long-term supply availability.

Q: Does the RoHS compliance change affect circuit performance?

A: No. ROHS3 compliance indicates the substitute parts meet current environmental standards by restricting hazardous substances. This does not alter electrical performance, response time, or breaking capacity. The fuse element and operational characteristics remain identical.

Q: Which substitute should I choose for new designs?

A: For new designs, select based on your assembly process: Tape & Reel variants for automated high-volume production, Cut Tape for flexible or manual assembly, and Tape & Box for mixed-volume scenarios. All are equally suitable from an electrical standpoint.

Q: Are all substitutes available in the same quantities?

A: Inventory levels vary by packaging format. The 0251002.NRT1L (Cut Tape) has the highest availability at 104,745 units. Tape & Reel variants range from 662 to 1,031 units. Verify current stock with your supplier for your specific volume requirements.

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